List of ER characters


The American medical drama ER features an extensive cast of fictional characters. ER aired on NBC from September 19, 1994, to April 2, 2009, and focuses on the lives of the doctors and nurses of the fictional emergency room located at Chicago's County General Hospital. The series lasted for fifteen seasons, and none of the main characters, who received starring billing at some point of the series, is featured in all fifteen seasons.

Main characters

The following is a list of characters whose portrayer received "Starring" billing at some point of the series. They are sorted by introduction to the main cast.

Mark Greene

Doug Ross

Susan Lewis

John Carter

Carol Hathaway

Peter Benton

Jeanie Boulet

Kerry Weaver

Anna Del Amico

Elizabeth Corday

Lucy Knight

Robert Romano

Luka Kovač

Cleo Finch

Dave Malucci

Abby Lockhart

Jing-Mei Chen

Michael Gallant

Michael Emory Gallant was a regular character from 2001 to 2004. Gallant first appears at County General Hospital in late 2001 as a medical student in his third year. Coming from a family with a military background, he had previously been on active duty as a member of the US Army Reserve, who is paying for his scholarship. During his time as a student there, he was assigned to Dr. Carter. He initially clashes with Dr. Pratt, a brash new intern who disparages Gallant's abilities. It comes to a breaking point early on when Pratt cracks a patient's chest without supervision and ropes in Gallant to help. However, over time, the two eventually become firm friends.
Shortly after arriving, Gallant accompanies Dr. Weaver to the scene of an ambulance that had been transporting a pregnant woman to hospital and been trapped under fallen power lines. While there, the power lines explode and Gallant saves a fireman from electrocution. He then helps Weaver deliver the pregnant woman's baby. The event gives Weaver a lot of respect for Gallant and his ability to keep his head under pressure.
In the following year, Gallant becomes close to fellow medical student Erin Harkins, though their relationship remains platonic. Later on in the year, Pratt and Gallant are arrested on suspicion of being the two gunmen at the 'Doc Magoos' shooting. Although they are innocent, and subsequently released, the incident shakes Gallant and his faith in the fairness and equality of the police. By the end of his time at County as a medical student, Gallant decides to apply as an Emergency Medicine intern and matches to County. Despite being a full-fledged doctor, he doesn't have any easier time. Only a few months in to his internship, a helicopter crashes in the ambulance bay and Gallant is in the thick of the action. Later that year, Gallant's sister comes to visit and during her stay, she spends the night with Pratt, which strains Gallant and Pratt's friendship, although they manage to remain friends.
At the beginning of Season 10, new medical student Neela Rasgotra has started her rotation at County. During this time, Gallant is keen in helping her settle in. Around April, Neela accidentally gives a patient the wrong medication. However, Gallant, who is supervising at the time, takes the blame When he is told he will be investigated, he reveals he has been called up for service, forcing the administrators to drop the investigation. He then soon reveals that he had feelings for her. However, before they can start a relationship, Gallant reveals to Neela that he has been called up to go to Iraq. They argue, but part on good terms.
Although Gallant had now left County as a regular character, he appeared in a few episodes during the following two seasons. In season 11, one episode kept jumping between County and Iraq. Gallant is now working in a military hospital. At one point, while out working in the field he is wounded by an Iraqi gunman. Gallant manages to shoot and kill his assailant before he can fire again. The incident haunts him, however. As well as treating injured US soldiers, Gallant's unit also treats injured Iraqi civilians. One day, a young girl arrives with severe burns, and Gallant insists that she has to be saved. With his commanding officer's blessing, Gallant organizes for the girl to be treated at County. He returns to the US with the girl and while on 72 hours leave, he renews his relationship with Neela. He returns to Iraq soon after.
The following season, Gallant returns home to finish his training as a doctor. Overjoyed in seeing each other again, Gallant and Neela make an impulsive decision to get married. They buy a house together and look ready to start a whole new life together. However, Gallant has a few emotional scars from the war; he revealed to Neela that he is going to counseling sessions for veterans, before revealing that he wants to finish his training in Iraq, by volunteering for a second tour of duty. Neela is shocked and angry with Gallant, but realizes that there is nothing she can do or say to stop him from going. For the third time, the two lovers part.
Gallant makes his final appearance in the penultimate episode of Season 12 "The Gallant Hero and the Tragic Victor." He is on a convoy of trucks, when the unit is ambushed by Iraqi insurgents. Gallant goes to the aid of a fallen officer and the convoy manages to escape. Gallant is unable to save the officer, however. Just as he has settled back down, a roadside bomb hits the truck and Gallant and the men on the truck were killed instantly. Two officers visit the ER later on and inform Neela of his death. The whole ER is shocked, especially Pratt, who takes his death hard. Gallant's belongings are given to Neela and it is revealed that he recorded himself on tape as a message to her just in case he died. On the tape, Michael apologizes to Neela for leaving her for Iraq.
During the 15th and final season of ER, at the end of the episode "The Book of Abby", long-serving nurse Haleh Adams shows the departing Abby Lockhart a closet wall where all the past doctors and employees have put their locker name tags. Among them, the tag "Gallant" can be seen.

Greg Pratt

Neela Rasgotra

Samantha Taggart

Ray Barnett

Ray Barnett is introduced in the eleventh-season premiere as a resident under the supervision of Dr. John Carter. He is a rebel and sometimes gets into trouble with his superiors, to the point that Chief of Staff Kerry Weaver gives him an ultimatum when he asks license to go on tour with his rock band. Weaver gets him to choose between his medical career and music. In the end, even at the suggestion of his bandmates, Barnett chooses medicine.
Barnett becomes Neela Rasgotra's roommate and starts to develop feelings for her, but he has a girlfriend named Katey, and Neela is married to Michael Gallant. Neela is also attracted to Barnett, but they never get into a formal relationship, even after Gallant's death. Their relationship becomes even more complicated with the arrival of Tony Gates. During Abby Lockhart and Luka Kovač's wedding, Barnett and Gates start a fight, which leads Barnett to leave the place, only to be hit by a truck immediately afterwards. As a result of this, Barnett loses both legs and moves back to Baton Rouge to live with his mother.
The character returns one last time near the end of the series, having received two prostheses. He explains that he works in rehabilitation, helping disabled and amputee patients. It is also revealed that he still has feelings for Neela. Neela decides to leave Chicago and move with Ray, to work in the same hospital.
Ray Barnett is portrayed by Shane West.

Archie Morris

Dr. Archibald "Archie" Morris is a fictional character portrayed by Scott Grimes on the television show ER.
The character of Dr. Morris debuts in late 2003, in the drama's 10th season, and is initially notable for providing comic relief. Morris is initially an inept second-year resident who avoids work whenever possible. Luckily, he is frequently bailed out by another resident named Nick Cooper. In the episode "Freefall", Morris is caught smoking confiscated marijuana by Dr. Robert Romano, but avoids punishment when Romano is killed by a falling helicopter in the ambulance bay. Unaware of the doctor's demise, Morris, stoned, waits at the admit desk to be disciplined, doing nothing to assist the other doctors as they deal with the fiery crash.
Morris's lack of commitment and slacking have already been well-established when his neglect costs a patient's life. The patient waits for hours to be seen by a doctor before she has a stroke and dies. Morris abruptly quits, storming out of the ER, only to return the next day claiming his father would deny him financial support if he didn't see this "thing" through.
Morris is made Chief Resident in season 11, allowing his character to further antagonize other characters. He achieves this coveted position because of a lack of competition, an eleventh hour push of publications, and an elaborate presentation for the interview. As Chief Resident, Morris's inflated ego often leads to clashes with colleagues, though he often acts as if he were beloved by his residents and medical students. Although Luka Kovac never has any disagreements with him, Ray Barnett, Neela Rasgotra and especially Abby Lockhart tend to mock and insult him for his pompous attitude, although in later years they regard him with grudging affection. Greg Pratt is initially also contemptuous of Morris, but by season 12 they are good friends. Kerry Weaver, on the other hand, although never openly rude to Morris, never views him as having much potential and does not support him as much as other ER doctors; she only gave him support as Chief Resident because he was, in her words, "a paperwork hound". Morris's leadership style swings wildly from delegation to micro-management. At the end of season 11, when Dr. Carter leaves the hospital, he tells Morris to "set the tone" just as Mark Greene had told him at the end of season 8. Morris is drunk at the time and doesn't recall the phrase when Carter asks him years later.
In season 12, it is revealed that Morris donated sperm many times earlier in his life. Four red-headed children, one of whom is African American, show up at the hospital and declare that Morris is their father. Although shocked by this, his comical attempts to be a "good dad" become a recurring theme for the character in subsequent episodes; the kids do love him, however. Later in the season, we learn that Morris has been hired by a pharmacy laboratory. In the season finale, "21 Guns," he is preparing to leave the hospital when a shooting occurs in the ER. Morris's quick and competent response to this crisis marks something of a professional turning point for him.
During season 13, Morris is hired as one of the ER's attending physicians. Morris begins a serious effort to win respect. Though other doctors still do not always take him seriously, he shows a moment of both care and skill when he correctly interpreted a young man's alternating demands to be admitted and discharged as symptoms of dissociative identity disorder. However, other doctors laugh at Morris's diagnosis and refused to authorize critical care, and he privately admits to Sam Taggart that he knows "most of the other ER staff think I'm a joke." Sam speaks kindly to him and then uses her communications skills to convince the patient to consent to life-saving treatment. This is where Morris slowly starts to become a much better doctor.
When new medical interns come to the ER, Morris's attention is caught by Hope Bobeck. Morris asks her out for dinner but she instead invites him to her Bible study group, as she is a born-again Christian. Morris pretends to be as devout as she is, and Hope and Morris grow close to each other. In the Christmas episode City of Mercy, he gets through a difficult shift as the only ER attending, and at the end of the day Hope tells him how much she has learned watching him. She then asks him out for drinks, with the implication of intimacy to follow. Morris declines, much to his own surprise, recognising that she is lonely and he would be jeopardising a longer-term relationship by taking advantage of that. Morris and Hope later get involved with each other while helping to plan Luka and Abby's wedding. The two take advantage of a honeymoon suite that Luka and Abby are not able to use and begin pursuing a relationship. Morris was saddened when Hope leaves for a long volunteer stint in Venezuela, and they subsequently break up.
In season 14, Morris discovers that his father has died, and laments to Abby that he and his dad never mended their long-broken relationship. He also fails his medical boards while Dr. Pratt passes them. Morris lies about his failure and asks Pratt to cover for him until he can take and pass his boards. Morris also undergoes brief therapy sessions after a hostage situation he was involved in, where the armed man was gunned down right after he gave himself up. Another hard hit comes when his friend Dr. Gregory Pratt is critically injured in an ambulance explosion and the ER staff are unable to save him. Morris takes Dr. Pratt's death harder than anyone else in the ER. In the following weeks, he clashes numerous times with the new chief Catherine Banfield whom Morris resents upon her arrival, seeing that she holds the position his deceased friend had earned. In the following weeks, Morris gets in trouble with Dr. Banfield for teaching new med student Chaz Pratt risky medical procedures that not even first year residents are qualified to perform. Morris admits that whenever he sees Chaz, he sees his brother Greg, and only wants to do the best for him.
As season 15 progresses, Morris is shown to have matured a great deal following Pratt's death, becoming the senior figure for the doctors in the ER, much like Mark Greene and John Carter before him. In many instances, his co-workers come to him for both personal and professional advice, although he retains his slightly comical personality. Specifically, Dr. Cate Banfield shares with him the fact that her young son died in the County ER, and Dr. Brenner admits to Morris that he was sexually abused as a child. Additionally, upon returning to the ER, John Carter notes that Morris took his advice on setting the tone. In the episode Separation Anxiety, Morris becomes attracted to a female patient whom he later learns is an undercover narcotics cop. In the episode "I Feel Good", Morris tells Claudia that he plans to one day propose to her, which she says she would accept.

Tony Gates

Simon Brenner

Simon Brenner is introduced as a new ER attending physician, first seen in bed with two women before arriving for his first shift. His character is superficially very charming, especially with the ladies. While Brenner is a talented physician, he is unwilling to share his knowledge and teach the new medical students. Even when consistently reminded that Brenner works in a teaching hospital, he still refuses to teach procedures to those who need or want the practice. He sleeps with one med student and later insults both her romantic and professional skills. When Pratt informs Dr. Anspaugh of Brenner's attitude, it is revealed that Brenner is Anspaugh's nephew.
At the end of season 14, Simon and Neela get into a heated argument in which she told him he was only at County because of his family ties to Anspaugh, attacked his attitude and told him no one else wanted him around. This leads to them sleeping together. They do so again in Season 15 and continue to spar like an old married couple. Simon is later shown with a girlfriend who is doing a thesis on Middle Eastern politics at the University of Chicago. Towards the end of Season 15 Neela tells him they have no romantic future together, although the pair eventually end their relationship amicably.
In the episode "Age of Innocence", it is revealed that Brenner was molested as a child by his mother's boyfriend. Morris wants him to get help to deal with the trauma, but Brenner tells him he is dealing with "in my own way". Later in "Shifting Equilibrium", Brenner is shown to be visiting a therapist and coming to terms with having been abused.
The series finale, "And in the End...", also shows Brenner mentoring and giving support to new medical student Julia Wise after the death of a patient.
Simon Brenner is portrayed by David Lyons.

Catherine Banfield

Supporting characters

Secondary doctors

Donald Anspaugh

Donald Anspaugh is a surgeon working at County General as well as the chief of staff and a member of the hospital board. The character was appointed County General's new chief of staff after South Side closed and merged with County. In his early appearances, Anspaugh was portrayed as a by-the-book doctor. In season four it is revealed that his son Scott has B-cell lymphoma. The cancer had previously gone into remission but has come back. Scott wants to give up and it is only through a personal connection with Jeanie Boulet in the ER that his spirits are raised. Noticing how well Boulet and his son relate, Anspaugh asks Jeanie to be his son's part-time private caregiver. She agrees and a deep friendship develops between Scott and Jeanie. Scott eventually dies.
In 1999 Anspaugh resigned as chief of staff because of his son's death and was replaced by Robert Romano. He remained both a surgeon and a leading board member but his exact position was unspecified for several seasons. He, along with Peter Benton, succeeds in saving John Carter's life after Carter and medical student Lucy Knight were stabbed by a patient. Anspaugh was present during Carter's intervention meeting when Carter's post-stabbing drug addiction was discovered at the end of season 6. At the end of season 8, he was among those who paid their respects at Mark Greene's funeral and assisted in the smallpox evacuation, trying to save Dr. Romano from losing his arm. Toward the end of Season 9, Anspaugh fired Romano over his insubordinate attitude and gave Kerry Weaver the job. In season 11's episode 19, Anspaugh's job again seems to change; he describes himself to Abby Lockhart as "the chief of surgery." He also participated in Susan Lewis' tenure-review panel. Anspaugh later resurfaced in Season 12 to deal with the lawsuit issue caused by Clemente. In the second episode of season 13, Weaver herself told him that it was her fault that Clemente kept working at County as long as he did, despite concerns from the staff and mishaps before. Dr. Anspaugh was originally going to fire Luka Kovac until Weaver spoke up. Afterwards, he immediately decided to relieve Dr. Weaver of her position of chief of staff, which he took over himself until a full-time successor was found. In Season 14, Greg Pratt appealed to Dr. Anspaugh to have him replace Kevin Moretti as Chief of Emergency Medicine, a proposal Anspaugh refused to accept despite Pratt's persistent efforts, citing Pratt's lack of leadership initiative and youth. Anspaugh opted to promote Skye Wexler instead. Dr. Anspaugh is seen throughout season 14, interviewing Dr. Pratt for the Chief's job, promoting Dr. Wexler and informing the ER of Dr. Moretti's departure and later meeting with Abby Lockhart and the rest of the board after her rehab stint. He then met with her again when she interviewed for an attending position.
Dr. Anspaugh was portrayed by John Aylward.

Victor Clemente

Victor Clemente first appears in the 250th episode of ER, "Wake Up", as a new attending physician from Newark who is seeking the Chief of Emergency Medicine position vacated by Susan Lewis and attempting to introduce modern equipment and diagnostics to the ER. He enters the series in an unusual way, by posing as a patient. This causes confusion and some irritation from doctors Abby Lockhart, Archie Morris, Gregory Pratt and especially Luka Kovač. Clemente and Luka clash over just about every case that comes through the ER, and Luka is so annoyed by Clemente that he decides to seek the ER Chief job for himself. Luka's main complaint with Clemente is that, regardless of whether Clemente is right or not, he will take the initiative on procedures whether he has the approval/opinion of other Attendings. Even if everyone working on a patient is against Clemente, he always seems to get away with it because Kerry Weaver likes his credentials. In the end, Kovač does become Chief, after which Clemente claims to have earlier decided not to seek the position, citing time constraints; Luka nonetheless takes steps to rein in Clemente's independent streak. The audience soon learns that Victor is not the consummate professional he was originally portrayed as. Clemente's former girlfriend Jodie, whose relationship with Victor in Newark caused unspecified problems that Kerry Weaver said were not his fault, tracks him down to Chicago and initiates a new relationship between them. This causes Clemente to become careless and even miss work to stay with her. Eventually, Jodie's controlling husband Bobby appears in his apartment. He shoots both Clemente and Jodie after Jodie asks for a divorce. Clemente has relatively minor injuries while Jodie ends up in a coma, but he becomes the prime suspect of shooting her and himself due to the cocaine found in his apartment and the fact that records in New Jersey show that Jodie's husband supposedly worked on the day of the shooting. Clemente is subjected to drug tests and is kept under close watch by Luka Kovač and other staff; Luka wants him gone but neither he nor Kerry take any steps to fire Victor from his job.
Jodie does survive and gets Clemente out of trouble by telling the cops what really occurred, but more problems occur when Bobby continues to harass Clemente by phone, stalk him by car, leave threats and make other comments to him. The comments indicate that he had tried to frame Clemente for an unspecified crime in Newark. In the episode "The Gallant Hero and the Tragic Victor", Clemente finally succumbs to the troubles plaguing him. Clemente's behavior includes relieving himself in public, property damage, and threats of violence. He is hospitalized at County and medically classified as being in an altered psychiatric state. A psychiatric consultant rules his peculiar behavior is caused by posttraumatic stress disorder or sleep deprivation, presumably from his vigilance in avoiding his stalker. In the Season 12 finale "Twenty-One Guns," Luka Kovač states that Clemente has finally been fired from his position at County, and Kerry faces stern questions from Dr. Anspaugh when a former patient files a lawsuit against Clemente and he is listed on a medical watchdog website as a bad doctor, leading to her initially throwing Luka under the bus. When the board plans to fire Luka over his Kerry-insinuated negligence in Clemente's hiring and terrible history at County, Kerry admits she was responsible for those problems, and is demoted from her chief of staff position as a result of that, which also contributed into her departure from the ER altogether in Season 13.
Dr. Clemente was portrayed by John Leguizamo.

Janet Coburn

Janet Coburn is the head of the OB department at County General Hospital, serving in that position throughout the entire run of the series. Coburn is frequently portrayed in some kind of conflict with the ER staff, most notably in her first appearance in season 1 when Mark Greene mis-diagnosed Jodi O'Brien who later died as a result. Her other appearances often revolve around the various pregnancies of different characters in the show, including Carol Hathaway, Elizabeth Corday-Greene, Chloe Lewis, and Abby Lockhart. Coburn later in the series revealed she once had a drinking problem and has since become Abby's Alcoholics Anonymous sponsor; she acts as both a no-nonsense mentor and a friend to Abby through the series. Coburn convinced Abby to get back into a program after she started drinking again, and also convinced her to fly to Croatia to make amends with Luka after revealing she was unfaithful. Dr. Coburn later appeared in season 15 to assist Dr. Rasgotra with a pregnant patient, and advise Dr. Banfield on IVF treatment.
Janet Coburn was portrayed by Amy Aquino.

Maggie Doyle

Maggie Doyle was an intern during season 3 and a resident during seasons 4 and 5. Maggie's older sister is identified as a former classmate of Carol Hathaway in a Catholic school. In the ER, she became friends with John Carter, who became attracted to her, but it is later revealed that she is a lesbian. During season 5, she accuses Dr. Romano of sexual harassment. She asked Elizabeth Corday to back her up, but Corday refused when Romano blackmailed her using some personal information. Kerry Weaver started an investigation and forced Romano to retract an inaccurate, critical review of Maggie's job performance, but this did not prevent Maggie from leaving the ER. Her absence from the show was not explained, but in the season 7 episode "Rampage" when Weaver & Romano were arguing over Dr. Legaspi's termination, Weaver suggested that Maggie Doyle was forced out due to Romano's dislike of gay people. Doyle could have left her job in the ER after the mess of the sexual harassment lawsuit she had on Romano was never going to be pursued.
9 years later in the season 15 episode "The Book of Abby", long-serving nurse Haleh Adams shows the departing Abby Lockhart a closet wall where all the past doctors and employees have put their locker name tags. Amongst them, the tag "Doyle" can be seen, the only former doctor on the wall to have not been a main character.
Dr. Doyle was portrayed by Jorja Fox. In real life, Fox left ER because she kept getting larger roles on successful drama shows, starting with The West Wing and peaking with her work as Sara Sidle on the hit show CBS drama .

Lucien Dubenko

Lucien Dubenko is the current Chief of Surgery. He was first introduced shortly before Elizabeth Corday departed, as an arrogant but obviously talented surgeon, bragging about, and then showing his ability to run the bowel with a laparoscope. Dr. Corday bitterly protests his hiring to Kerry Weaver but presents no real reason for her hostility and leaves Kerry confused and annoyed about why Corday "is taking this so personally". Corday's anger causes her to conduct an illegal organ transplant between two HIV+ men, which leads to her being reprimanded and being forced to take a demotion. Corday eventually quits the hospital altogether, though Dubenko praises her actions in doing the transplant. Dubenko is portrayed as a very dedicated and talented surgeon, with a keen interest in medical science, lecturing the interns on physiology. Dubenko becomes friends with residents Abby Lockhart and Neela Rasgotra, and later seems to fall for both of them, most notably Neela after she becomes a surgical intern. He did his trauma fellowship at Johns Hopkins Hospital in Baltimore, MD. Due to his connections, he helps Tony Gates get a 13-year-old ICU patient into a clinical trial there. He has an older sister named Victoria who lives in an assisted-care facility in Evanston, IL because she was in a car crash on prom night caused by her drunken teenage boyfriend that left her with brain damage at age 17. He was 15 at the time. He mentions an ex-wife. After he discovers he has prostate cancer in Season 12, he asks Abby to have sex with him to make sure he is fully functioning after surgery, but reacts with equanimity when she declines the offer. During Luka and Abby's wedding, he asks Luka to take care of Abby. He was involved in a "friends with benefits" relationship with new ER Chief Dr. Skye Wexler, which later ended after he lashed out at her for excluding him from her life and accused her of being a slut. He later resigned in protest over the death of patient Sheryl Hawkins, when he had to leave the OR and leave Dr. Rasgotra to finish the operation, because he was the only surgical attending available in the hospital, this outburst enraged Dr. Anspaugh during the M&M. Efforts by Neela and Simon Brenner led to his return in Season 15, and he later justly criticized Neela for her dismissive attitude towards teaching surgical residents by giving her the choice of doing her job well or getting the hell out of County. Although arrogant and awkward in social situations, Dubenko is a dedicated and effective teacher and shows compassion towards his patients when he can.
Dr. Dubenko is portrayed by Leland Orser.

Angela Hicks

Angela Hicks arrived in the Season One episode "Blizzard", and had to start working immediately because of a blizzard which led to many patients visiting the ER. She worked at County General between 1994 and 1997 and gave both Peter Benton and John Carter advice in many aspects. Dr. Hicks' absence was never explained, although she was virtually sidelined after John Carter left her team to transfer to Emergency Medicine and Peter Benton left to join Romano's team instead. Though she stopped appearing her locker could still be seen in the background for a few more years.
Dr. Hicks was portrayed by CCH Pounder.

Jack Kayson

Jack Kayson is the chief of Cardiology and member of the hospital board. He usually appears in board discussions, and is sometimes called down to the ER for cardiology consults. He has at times, been shown doing procedures in the cardio cath lab. He is easily angered when residents in the ER question his medical decisions. In the first season, Kayson had a disagreement with Susan Lewis about the treatment a patient should receive who had a myocardial infarction. Susan tries to give the patient the correct treatment but he overrules her, the patient dies, and Kayson later hauls Susan in front of a hospital review board—only to see the board largely side with her and chastise him for his behavior. Later Kayson is admitted with the classic signs of an acute myocardial infarction and Susan gives him the treatment he wants and eventually saves his life. After this, Kayson asks Susan to be his Valentine's date, but Susan declines. He later clashed with med student Michael Gallant over the death of a hypochondriac and tried but failed to stop Dr. Greg Pratt from helping treat desk clerk Frank after he suffered a massive heart attack. Dr. Kayson later returns twice in season 11, in which he is on the Hospital Board that investigates Dr. Elizabeth Corday. Then later returns to treat patient Jules "Ruby" Rubadoux with Dr. Anspaugh. Dr. Kayson is not seen again until season 14 in which he misdiagnoses a patient and argues with Dr. Gates.
Dr. Kayson is portrayed by Sam Anderson.

Abby Keaton

Abby Keaton was a pediatric surgeon from Southside Hospital reassigned to County when Southside closed. She supervises a pediatric surgical rotation with Dr. Benton. Eventually, she begins a clandestine relationship with Dr. Carter, but their relationship ends when Keaton leaves for a volunteer mission to teach Pakistani surgeons.
Dr. Keaton is portrayed by Glenne Headly.

Gabriel Lawrence

Gabriel Lawrence is Kerry Weaver's mentor. She hired him as the new Senior Attending Physician in the ER at County General. During his brief appearance, Dr. Lawrence shares his experiences with the members of the ER staff. It quickly becomes apparent that Lawrence is in the early stages of Alzheimer's disease. Mark Greene's well-founded suspicions are mistaken for jealousy, and Lucy Knight's notice of this is also dismissed by John Carter. At first Lawrence does not want to admit to what is happening, but the signs of his mental deterioration soon become readily apparent. These include sudden bursts of irritability, being unable to find the right word, leaving his reading glasses in the lounge freezer, and looking for his car on the wrong floor of the parking garage. After Greene stages a scene with a fake ER patient to point out these problems, Lawrence realizes he has no choice but to retire. He makes amends with his son in California, and goes to live with him. As he waits for his son to pick him up, he gets the chance to make one more diagnosis and save one last life—a patient with a rare case of strychnine poisoning that had baffled other ER physicians.
Lawrence was portrayed by Alan Alda. At one point he mentions that he worked for the U.S. Army, a nod to Alda's role as Hawkeye Pierce in M*A*S*H. Alda received an Emmy nomination for his portrayal but lost it to James Whitmore. Alda said that his great experience working with John Wells in the role of Lawrence led him to accept the role of Arnold Vinick on Seasons 6 and 7 of The West Wing.

Amanda Lee

Amanda Lee joined the staff of County General Hospital as the new Chief of Emergency Medicine, replacing Dr. Kerry Weaver, who had been interim chief in the wake of Dr. David Morgenstern's retirement following his heart attack. While she appeared normal on the outside, it became clear that Lee had serious emotional instabilities. In particular, she obsessed over Dr. Mark Greene, writing erotic stories featuring him, stealing his gloves and lab coat, and decorating her Christmas tree with twin heart-shaped ornaments bearing their faces. It also seemed that she confabulated quite extensively; several times, she mentioned a major incident in her life in response to someone confiding a similar incident to her.
Dr. Greene became suspicious after he could not verify Lee's claim – one of her confabulations – that she had published an article in a Cornell University publication while still a third-year student. A copy obtained online attributed the article to "A.W. Lee" and pictured an Asian male in his 40s; Lee claimed he was a classmate that she was often confused with and that the following month's publication had corrected the error. When Greene attempted to check out the original journals from the hospital library to review additional articles written by Dr. A.W. Lee, he found that they had been checked out. In fact, Lee herself checked them out and removed the three articles with a razor.
After intercepting a message from Cornell University for Mark – he had been trying to verify whether or not Lee actually had graduated from there – Lee snapped. She locked Mark in the CT scanner room when he was calming a patient suffering from agoraphobia after her CT scans. Lee accused Mark of being uncaring and hateful, then removed her lab coat and fled. By the time the CT technician returned from lunch, Lee was long gone. Upon contacting the authorities, the hospital learned that "Dr." Lee had never graduated but had obtained a residency using the credentials of the same A. W. Lee whose journal articles she claimed to have written. It was also mentioned that she has had other names and professions such as lawyer and architect by pulling the same scams she did in order to be a doctor.
She was portrayed by actress Mare Winningham.

Kim Legaspi

Kim Legaspi first appears in season 7 and is introduced as a psychiatrist. Kim later gets involved in a friendship with Kerry Weaver that turns into more than a friendship after Kerry realizes she is a lesbian. Their relationship does not last long because Kerry is in the closet and uncomfortable at being in public with Kim. When Kim is falsely accused of sexual misconduct on a case, Dr. Romano leads a witch hunt and Kerry does not support Kim, leading Kim to break off their relationship. Kerry later tries to reconnect with Kim but Kim had moved on to a new partner. In the season 7 finale "Rampage", Dr. Romano fires Kim when she doesn't immediately answer a bogus page from him, and later cites more bogus reasons for terminating her to an aghast Kerry Weaver. Though Kerry comes out to Romano and says she'll fight him over his treatment of Kim, it's revealed in the Season 8 premiere that Kim quit at County and took a new position in San Francisco.
Dr. Legaspi was portrayed by Elizabeth Mitchell.

Kevin Moretti

Kevin Moretti was Chief of Emergency Medicine, sarcastically dubbed 'Mussolini' by Abby Lockhart for his Italian surname and stern manner of running the ER in order to maximize efficiency. Following the departure of Dr. Kerry Weaver and the resignation of Dr. Luka Kovač, Dr. Kevin Moretti is moved from the intensive-care unit to take charge of the ER. His early appearances provoke much conflict with the ER Staff, particularly Abby and Pratt who find his "style" to be harsh and abrasive. Despite this, he proves to be intelligent and quite adept at attending/diagnosing patients, and his system seems to work. During a blackout-ridden Chicago night, he and Abby have an alcohol-fueled one night stand. After having a difficult visit from his troubled son, he finds out the son is having serious problems at college and takes personal leave to go help him. He intended his absence to be temporary, but it later proved to be permanent and Dr. Skye Wexler was appointed acting chief in his stead. Dr. Moretti later returns in the Season 14 Finale and apologizes separately to Abby and Luka for his role in their marital crisis. Abby is nonplussed by his explanation and doesn't talk very long to him, while Luka listens to Moretti's apology and then punches him in the jaw. Moretti remarks, "I guess I had that coming." as Luka walks away.
Dr. Moretti was portrayed by Stanley Tucci.

David Morgenstern

David Morgenstern was the chief of surgery and head of the ER until 1998 when he resigns shortly after he has a heart attack. His background was a combination of Scottish and Russian-Jewish.
Morgenstern first arrived at County in 1968 as a volunteer in his pre-med days. He was mentored by Dr. Oliver Kosten, a young ER physician whose visions of better patient care eventually translated into an expanded and more functional ER.
David Morgenstern is responsible for a sage piece of advice that has been handed down throughout the series. In the pilot episode, when Julianna Margulies's character, nurse Carol Hathaway, is brought to the hospital with a drug overdose, Morgenstern tells Dr. Greene that he needs to "set the tone" to get the unit through the difficulty of treating one of its own.
Dr. Morgenstern worked at County General Hospital until 1998 after he made a mistake during a surgery and tried to make Dr. Peter Benton the scapegoat. After Benton was suspended, Morgenstern admitted the truth to the hospital and told it to Benton in County's parking lot and resigned because the incident showed "I'm not a very great man, and that's what I need to work on."
Morgenstern returned to the ER in 2009 when his mentor, Dr. Kosten, wanders from his nursing home and returns to the ER he was instrumental in building. Morgenstern reveals to the current ER staff the dramatic impact his mentor had on himself as well as on the entire hospital.
The character was portrayed by William H. Macy.

Skye Wexler

Skye Wexler was a locum hired by Dr. Kevin Moretti to help alleviate the staff situation. Initially, Skye was only in Chicago for a few months earning some extra money to fund a surfing trip. But following Moretti's sudden departure, communication in the ER broke down and Skye spoke up that a new chief was needed right away. Much to her surprise, not to mention Pratt's, Anspaugh appointed Skye as the temporary head of the ER. Skye told Anspaugh that she did not want that job as she was not planning on staying in Chicago but Anspaugh pointed out that she was the most qualified member of staff and gave her an ultimatum: all or nothing. Following Skye's promotion, Pratt considered handing in his notice feeling undervalued but later changed his mind. Skye later got involved in a "friends with benefits" relationship with Dr. Lucien Dubenko. The relationship with Lucien ended due to his jealousy when Skye begins a friendship with ladies man Dr. Simon Brenner and also when she kept dismissing his efforts to become more involved in her non-sexual social life.
Dr. Wexler is portrayed by Kari Matchett.

Secondary nurses

Haleh Adams

Haleh Adams, portrayed by Yvette Freeman, is a nurse in the ER of County General Hospital. She is one of only six characters to appear in every season. Her appearances were less frequent in the 1997–1998 and 1998–1999 seasons, as Freeman was appearing in the sitcom Working. In the 2002 season, she returned with a new appearance after losing 120 pounds, but subsequently gained some of the weight back.
Haleh is a confident and skilled nurse who at times displays a motherly disposition to the staff. When Ray Barnett protests angrily at Haleh being allowed to evaluate him to Susan Lewis, Lewis sharply tells him, "Haleh has been here longer than anyone- she knows what she's talking about." Not one to be taken for granted or put upon, Haleh stands up for herself; often making her point with a sharp sardonic wit. She has been Nurse manager two times over her 35 years at County; in 1997 when Carol Hathaway was home following her suspension from the ER and between 2000 and 2002, doing a terrible job in her first time there but a competent one the second time around. She has sung at both Christmas and Halloween parties in the ER and has a truly fantastic voice. Haleh has been fired for short periods twice: during one episode in season 9, she was fired for a few hours by chief of the Emergency Room Robert Romano, but returned when Romano learned that nurses had lots of syndicates to protect them. In season 12, the new chief nurse Eve Peyton, Samantha Taggart fired her but she was later rehired when an airplane exploded over the city shortly after takeoff and County was seriously short on nurses. Sam called her in while Eve was away. Eve told Sam that it was a good move.

Dawn Archer

Dawn Archer appeared as an ER nurse beginning in season 13. Not much is known about her other than she is originally from New Orleans and was displaced in Hurricane Katrina. During her time on the job, she has developed friendships with fellow nurses Chuny Marquez and Haleh Adams, and to a lesser degree, Sam Taggart.

Wendy Goldman

Wendy Goldman was one of the regular nurses from the first three seasons of ER. Her character had a sweet and innocent demeanour, and frequently featured in comical subplots. Her first episode was in the pilot, "24 Hours", in 1994. Her absence from the show was explained by Kerry Weaver in season 4 when she says that two nurses left and Yosh Takata was hired to replace them. Goldman's name was never mentioned again after she stopped appearing.
Wendy was portrayed by Vanessa Marquez.

Lily Jarvik

Lily Jarvik is one of only six characters to appear in every season of the show, having made her first appearance in episode 1.08 "9½ Hours". Since then she has proved to be a valuable resource in the County General Emergency Department. She is generally seen in the trauma rooms and keeping the floor running during major incidents. Not much is really known about Lily as she was never been given much of a storyline to truly develop her character.
Lily Jarvik is portrayed by Lily Mariye.

Chuny Márquez

Ethel "Chuny" Márquez is one of six characters who has been in all seasons of ER. She has often assisted in translating for Spanish-speaking patients. Chuny has had a relationship with Mark Greene in season 3 and with Luka Kovač in season 9. After her relationship with Luka became problematic, she complained to Kerry Weaver who almost fired Luka. Later, when Chuny comments on how good Carter looks in a black suit, he reminds her about the "sexual harassment" complaints against Luka. She proved to be good friends with many of the nursing staff and attempted to set Samantha up with their self-defense trainer
It is revealed in season 14 that Chuny's real name is Ethel.
Laura Cerón has appeared in more episodes than any other recurring guest star, and is the only recurring guest star to have appeared in more than 200 episodes. Only main cast members Noah Wyle and Laura Innes appeared in more episodes.

Chuck Martin

Chuck Martin was a flight nurse and ex-husband of Dr. Susan Lewis. They met during a trip to Las Vegas, in which they got drunk and later married. After they return to Chicago, they have the marriage annulled, but this did not stop Chuck and Susan from further dating. Chuck was injured in the helicopter crash on the roof of the hospital and had emergency surgery to remove his spleen. In this same crash, Dr. Romano was killed as the helicopter fell off the roof and landed on Dr. Romano on the ground. Susan later had a baby boy named Cosmo, whom Chuck looked after when Susan was promoted to Chief of Emergency Medicine after Dr. Romano's death. When Susan accepted a tenured position at the beginning of season 12, Chuck and his family move to Iowa. In Sherry Stringfield's return appearance in the series finale, however, Susan mentioned that she was dating again, suggesting that she and Chuck were no longer together.
Chuck was portrayed by Donal Logue.

Malik McGrath

Malik McGrath, along with nurses Haleh, Chuny and Lily, and paramedics Dwight Zadro and Doris Pickman, has appeared in every season since the pilot. He has given the ER some comic relief and appears to be good friends with desk clerks Frank Martin and Jerry Markovic, to whom Malik once played a joke on, during his birthday surprise party. It's also revealed that he gets very little pay despite his experience and for this does not protest his hours getting cut. He is an LPN- licensed practical nurse instead of an RN- registered nurse like most of the other ER nurses. In the episode where all the nurses strike Malik continues to work and states that he doesn't have to worry because it doesn't get much cheaper than an LPN, so he was safe. He was good friends with Abby Lockhart, having worked with her during her years as an ER nurse.
Malik was portrayed by Deezer D.

Conni Oligario

Conni Oligario was a nurse in the ER since the first season in 1994 until 2003 when she was fired during the reign of terror by ER chief Robert Romano in season 10. Conni and fellow nurses Lydia and Yosh protest their treatment and ask chief nurse Abby Lockhart to talk to Romano about it. When Abby is unable to address Romano, the three nurses are replaced and each given a 90-days suspension. Conni was never seen again in the ER after the suspension, although in Season 12's episode "Blame It On The Rain", Haleh mentions she's covering for Conni.
Conni Oligario was portrayed by Conni Marie Brazelton.

Eve Peyton

Eve Peyton, Ph.D., served briefly as chief nurse in the ER and worked closely with Dr. Victor Clemente. Her abrasive and unpleasant personality became especially clear when she forced Samantha Taggart to fire Haleh. Eventually, Eve herself was fired on Christmas Eve for punching a drunk patient who mocked some blind children and pouring urine on him. She has the skills of a doctor in medicine but does not hold a license to practice as one. An example of this is when she shows to have more knowledge of drugs, procedures, and emergency medical care than most residents and students. She has also been better at performing emergency procedures than most residents and medical students. She also enforces most physicians and senior nurses to teach inexperienced hospital doctors, students, and nurses, and is a staunch defender of nurses' rights. But she also had a hostile attitude towards most if not all of her working ER nurse staff; nearly all the doctors apart from Weaver instantly disliked her, and many of the nurses eventually began to turn against her. Sam Taggart was the only one who became friends with Eve, yet Eve made sure to label Sam "Judas" after her dismissal, leading Sam to simply watch Eve leave the ER forever in silent sadness.
Eve was portrayed by Kristen Johnston.

Shirley

Shirley is a female surgery nurse usually seen either in the operating room or just outside, informing the surgeons about matters that are needed. She is also often seen at the surgical level front desk, informing people of whatever information she has received from the hospital's doctors. Being a surgery nurse she is rarely seen down in the ER or trauma rooms, but more in the OR, so she is usually seen working with doctors such as Elizabeth Corday or Peter Benton rather than doctors such as John Carter or Kerry Weaver and other staff nurses such as Chuny or Haleh.

Yoshi Takata

Yosh "Yoshi" Takata, portrayed by Gedde Watanabe, was the second male nurse introduced in ER, after Malik McGrath. Takata's character is Japanese, gay, and a convert to Judaism. He was hired in the episode the same day that Jeanie Boulet was to be fired by Kerry Weaver due to budgeting. Takata's hiring, however, cast doubt in Boulet's mind about whether budget issues had really caused her layoff. Along with fellow nurses Conni and Lydia, Yoshi is laid off in the tenth-season episode by character Dr. Romano during hospital staffing cuts and did not return to the show.

Lydia Wright

Lydia Wright-Grabarsky was the second character to be introduced in the pilot episode of the ER. She is seen waking up Mark Greene. She was a very experienced nurse and had developed some remarkable skills, including the ability to very accurately diagnose a patient's blood alcohol level simply from smelling their breath.
She marries police officer Alfred Grabarsky in season 3. They get married in the Emergency departments waiting area. Lydia appears for the next-to-last time in 2003 when Dr Romano decides to cut senior nurses for cheaper labor. Lydia, along with Conni and Yosh were fired after protesting their reduced schedules.
Lydia returned in the 2009 series finale. She is again working at County and wakes Archie Morris as she did Mark Greene in the pilot episode. She explains that she has been working nights so she can babysit her grandchildren.
Lydia was portrayed by Ellen Crawford.

Desk clerks and other non-medical staff

Miranda Fronczak

Miranda Fronczak, better known to the staff as "Randi", is hired as a Desk Clerk in Episode 028 "Do One, Teach One, Kill One". The character is portrayed by Kristin Minter.
A good looking assertive woman, Randi is not afraid to get her hands dirty or deal with hostile patients. In Episode 031 "Days Like This", she knocks out a violent patient with Dr. Weaver's crutch after he has knocked down both Weaver and Jeanie Boulet. In that same episode it is revealed that she is on probation when Randi casually refers to her parole officer. This comment leads to a great deal of speculation among the staff about what she went to prison for, including a betting pool. It is ultimately revealed by Randi that she went to jail for "malicious mischief, assault, battery, carrying a concealed weapon, and aggravated mayhem."
Randi is a bit of a rebel and is often seen wearing unprofessional attire more suitable to a club than an ER. Some of her clothes are designed and made by herself, and she attempts to market them under the label "Randi wear". When Weaver confronts her about her wardrobe, Randi replies that she is dressing more conservatively than normal; a revelation which leaves Weaver uncharacteristically speechless. She continues to get away with wearing whatever she wants throughout her many years of service in the ER. Later in season 5, Randi actually helps Weaver put together an outfit for her interview for the position of Chief of Emergency Medicine.
During season 6 Randi punches an extremely obnoxious man who sets off the fire alarm in order to get attention as he has a migraine. She is last seen in the Season 10 episode "Shifts Happen" dancing to hip hop music at the front desk with Dr. Pratt at 3:00 AM. Her departure from the ER staff was never mentioned or explained.

Cynthia Hooper

Cynthia Hooper, portrayed by Mariska Hargitay, first appears in Episode 071 "Something New" as an applicant for the job of ER desk clerk. Her interview with Mark Greene and Carol Hathaway does not go well as she appears very emotional and somewhat unreliable and inexperienced given her work history. She has also forgotten her references. Cynthia waits until Mark has finished work and asks if she can talk about the job. In talking with her, Mark discovers that she is new to Chicago and feels sympathy for a lost soul in a new city. He invites her to get some coffee and, having made a personal connection with her, gives Cynthia the job without discussing it with Carol.
Mark's decision to hire Cynthia is met with some hostility and her inexperience leads to some initial problems at the ER. Friction develops between Cynthia and some members of the ER staff, particularly Carol who did not want her to be hired in the first place and lashes out at Cynthia whenever she does anything wrong. Meanwhile, Mark and Cynthia continue to develop a friendship and eventually end up in a relationship together. Their relationship, however, is somewhat dysfunctional as Mark is just having some fun after his recent emotional traumas and Cynthia is truly in love with Mark. When Mark's mother becomes seriously ill, Mark goes to California to be with his parents. Uninvited, Cynthia decides to surprise Mark by going out to California to support him and his family. She is surprised to find Mark annoyed by her arrival, which causes awkwardness between them. Mark ultimately admits to Cynthia that he is not in love with her, and upset, Cynthia returns to Chicago.
On returning to Chicago, Mark finds that Cynthia has quit her job without leaving a forwarding address. Unhappy with how things ended, Mark uses his doctor status to find Cynthia's new address. He goes to her new apartment to apologize and return some of her possessions. He is surprised to see she has regained custody of her young son, and when he tries to make amends and resume their relationship, she is kind but firm in stating "You don't love me. I deserve better" and getting him to leave, politely but permanently.

Jerry Markovic

Jerry Anthony Markovic was desk clerk of the emergency room and later promoted to supervising emergency services coordinator The character was portrayed by Abraham Benrubi.
Jerry was comic relief on the series. The character was mostly seen playing jokes on other staff members, organizing parties and celebrations, trying to make money on the side via various get-rich-quick schemes and making humorous remarks. During the fourth season, Jerry accidentally blew up an ambulance with a grenade launcher; this led to a suspension from day turns by Kerry Weaver, thus Jerry was forced to attend at nights, but he would get his job back on days later that season. Jerry was last seen at the end of season 5. To date, there has been no official explanation for the character's absence during that period, not even from Benrubi himself. Because of his great height and girth, Jerry is also used as a bouncer if patients or customers become aggressive, although he claims he avoids violence and generally has a gentle nature.
It was not until season 8 that Jerry was called back to work after members of the staff became sick. When asked about where he's been for the past three years, he replied that he had been in "retirement." During that time, he developed some rivalry with fellow desk clerk Frank Martin, to the point that they were involved in a fight in which they crashed on Dr. Chen. Jerry and Frank received a warning from Dr. Weaver, and since then Jerry and Frank seemed to be getting along better, and later became friends, as shown when Frank suffered a heart attack, a fact that really concerned Jerry. Equally, Frank was deeply affected when Jerry was shot in the 12th-season finale.
Jerry's mother is introduced in the first episode of season 13 when her son was treated by some members of the staff after he was shot by Samantha Taggart's ex-boyfriend Steve Curtis, who went on a rampage in the emergency room in season 12's finale. During the assault, Jerry was shot while protecting a boy. Jerry's mother reveals to Archie Morris that she applied to Harvard four times for him, but he was never able to make it into college, and complains about Jerry's paycheck. Jerry ultimately survives the surgery, but was never seen again in the ER. In an episode during the 14th season, Frank remarks that Jerry officially quit and is now "slinging beers in Alaska," a reference to Benrubi's character Ben Tomasson in the ABC television series Men in Trees.
The character of Jerry's mother was played by Seinfeld's Estelle Harris in "Bloodline," but she also appeared in a long shot in "Don't Ask, Don't Tell," berating him for using her trashcans to trap a kangaroo on the loose. The episode was also one of the last episodes to show Jerry smoking a cigar.
In the Season 15 episode "The High Holiday", Jerry returns to Chicago as he got tired of Alaska, and was first amicably welcomed back by Frank and Morris. Although he has not had any luck getting a job, he is presumably re-hired at County General because Dr. Banfield needs someone to cover for Frank, who is under the influence of marijuana-laced brownies. He is seen in the "Dream Runner" episode and it is assumed that he has his old desk clerk job back.
Jerry is also a Universal Life Church Minister, and officiated Neela and Michael Gallant's wedding in the episode "I Do." His politics seemed too progressive, often clashing with Frank's law and order conservatism. Jerry is single and there was no mention of him being married or having a girlfriend, although at the beginning of "The Gallant Hero and the Tragic Victor," he turns down Dr Clemente's offer of a beer because he's meeting a "lady friend." However, in S15E16 'The Beginning of the End', Jerry, free of inhibition under the influence of a mushroom-derived toxin, makes a pass at a returning Dr John Carter – telling "Dr. Carter, call me."
In the episode, "Blame It on the Rain," it is revealed that Jerry is deathly afraid of thunderstorms—mainly because he has been hit by lightning on several previous occasions, a fact that everyone in the ER knows but Kerry Weaver, who sent him out in a storm to get a gift for her son Henry's birthday. He returns several hours later, dazed and holding a scorched paper bag. Frank asks him, "You got hit by lightning again, didn't you?" to which he only nods. At first Kerry does not believe him, but Jerry finally manages to get out the words, "Here's your change," then hands her a bunch of coins that have been fused together. Needless to say, she's thoroughly convinced.
In a 12th-season episode, it is revealed that Jerry is also fluent in American Sign Language, when he is asked to interpret for a boy who was trying to bring a drugged girl to the ER and wound up being assaulted due to a misinterpretation by the police.
Up until the third season, Jerry was a cigar smoker, but after the episode "Don't Ask, Don't Tell," the character was not seen smoking again.
Jerry's age has never been given on the show, although it is presumed that he is the same age as Benrubi himself, although when he returned after three seasons, Jerry's hair and goatee are gray, so it is possible he could be older.

Frank Martin

Francis "Frank" Martin first appeared as a police officer who was shot in his foot in the first episode of the show. He was Dr. Carter's first patient and then as a desk clerk in the Season 6 episode "Such Sweet Sorrow," temporarily replacing Jerry Markovic. Troy Evans, the actor who portrays Frank, had previously made a guest star appearance in the pilot episode "24 Hours" as a character named "Officer Martin." When Frank arrives to start as desk clerk, he mentions to Weaver that he had previously worked as a Chicago policeman for 26 years. During his commentary on the ER season 1 DVD set, Michael Crichton confirmed that Frank and Officer Martin were the same character.
Frank exhibited a more traditionalist, conservative, law and order type of philosophy that often put him at odds with some of his more liberal co-workers, especially in matters of sex outside marriage; when giving the expecting Abby Lockhart a gift basket, he remarked, 'That's for you and the little bastard". He ran background checks on patients in order to help the police round up criminals, opposed giving medical care to illegal immigrants, and attempted to beat up a homeless man with a stick. He was almost as overtly racist and bigoted as Dr. Romano; his statements about women, minorities, gays, lesbians, and the indigent were often politically incorrect and deeply insensitive. However, unlike Romano, Frank was a generation out of step and eventually his attitude began to mellow; in later seasons, very few of his inappropriate comments had real malice attached to them. When asked for information by the staff Frank typically gave a very sarcastic response, then refers them to what they need. Despite his attitude, most of the doctors and nurses regarded him with a mixture of affection and exasperation- especially Neela Rasgotra and Luka Kovac, both of whom are non-American nationality and thus put up with Frank's insults often. Frank also tends to show a bit more patience and concern around children, and when a ten-year-old girl who had been kidnapped and raped for months died from gunshot wounds in the ER even Frank was too appalled to say anything witty.
When Jerry came back to work, he and Frank fought over politics, eventually coming to blows and injuring Dr. Chen by accident. She prevented Weaver from suspending them by claiming that she tripped and hurt herself, then ordered Jerry and Frank to agree to learn to work together. The relationship between the two men became quite cordial, eventually developing into a genuine friendship; when Jerry was shot and nearly died in the Season 12 finale/start of Season 13, Frank was constantly at Jerry's side.
In the Season 10 episode "Forgive and Forget," Frank suffered a heart attack while at work. Ironically, his life was saved primarily by two minority staffers: English-Indian medical student Neela Rasgotra, who found him collapsed on the floor; and African American Dr. Greg Pratt, who successfully performed a life-saving procedure on Frank, using a syringe to remove blood that had accumulated around his heart. This episode also revealed that Frank was not only a former police officer, but also a Vietnam War veteran with high regard for his fellow soldiers, a loving husband, and a devoted father to a developmentally disabled daughter. All this offered a more complex illustration of his life and contradicted his workplace reputation as an elderly grouch. It was also more or less confirmed that Frank was indeed the same Officer Martin who shot himself in the foot in the show's debut.
Following the heart attack, Frank remained predictably cantankerous, though in some ways the character seemed to become a nicer man—particularly to Neela and Pratt. When Greg Pratt died in the Season 15 premiere "Life After Death," Frank was deeply shaken and upset. Upon Neela's departure from County in the Season 15 episode "Shifting Equilibrium," Frank threw her an elaborate farewell party that focused on Neela's Indian heritage.
Despite his personality, he does show a deep liking to other doctors, such as Archie Morris and John Carter. He spoke in defense of Morris to Banfield, explaining Pratt's death affected him harder than most. He welcomed Carter back when he returned with a pregnant Kem, and wished him good luck in him getting his kidney transplant.

Timmy Rawlins

Timmy was one of the many special County General ER staff members that was in the show's 2-hour pilot episode. Halfway into the show's first season he disappeared without any explanation. Years later in season 13 he was brought back into the show and resumed his position as a desk clerk on the staff of County General's ER. It was explained in his return to the show in season 13 as to why he left County he said it was because he had felt trapped in Chicago and needed to do something new, so he left to travel the world.
Later in the season he went on a cruise with Charge Nurse Samantha Taggart's grandmother Gracie and even though the cruise was only supposed to last 1 week they ended up gone for 2 months which he explained was because they went to Singapore and they also later got stuck at the Cambodian border.
He disappears without any explanation after the season ends.