A guard from Kansas City, Missouri, Harrison played college basketball at Tulsa, turning down an offer from Kansas to play football. He was a four-year starter for the Golden Hurricane. As a senior, he was named American Athletic Conference Men's Basketball Scholar-Athlete of the Year after averaging 14.8 points, 5.5 rebounds and 4.1 assists per game while maintaining a 3.135 grade-point average. He is the only player in Tulsa history to register 1,300 points, 400 assists, and 200 steals in his career. However, he struggled with his shooting, hitting 19.5 percent of shots from behind the arc and 63 percent of his free throws.
On February 21, 2018, the Phoenix Suns signed Harrison to a 10-day contract. Two days later, he made his NBA debut, recording 4 assists and 4 steals in a 128–117 loss against the Los Angeles Clippers. Harrison would sign his second 10-day contract with Phoenix on March 3. The next night, he would have his first start in the NBA under a loss against the Charlotte Hornets, playing a total of 30 minutes and recording a then-season-high 14 points that night. On March 13, 2018, Harrison was signed to a multi-year deal with the Suns, guaranteeing him at least the rest of the season, if not more than that. On March 28, Harrison would record a then-season-high 17 points as well as four steals in a 111–99 loss to the Clippers. On April 10, Harrison would record his first double-double with a career-high 18 points and 10 assists in a 124–97 blowout win over the Dallas Mavericks. On July 1, it was announced that Harrison would play with the Phoenix Suns once more, joining them for the 2018 NBA Summer League. Harrison performed as one of the team's better players throughout the event, averaging 12.2 points, 6.6 assists, 4.6 rebounds, 2.4 steals, and 0.8 blocks in 27.2 minutes per game in five games played for the team. As a result, the Suns announced they plan on making Harrison's roster spot with Phoenix at least partially guaranteed for the upcoming season. He would earn part of his guaranteed deal for the upcoming season on August 1. After the August 31 trade where the Suns moved both Brandon Knight and Marquese Chriss to the Houston Rockets for Ryan Anderson and rookie point guardDe'Anthony Melton, general manager Ryan McDonough expected that Harrison would get more of a playing opportunity with the Suns either as a potential starting point guard or as a back-up point guard again if the team found another trade before the season began. However, after competing with returning point guard Isaiah Canaan and rookies Élie Okobo and De'Anthony Melton for the chance at being a starting point guard during the preseason, the Suns waived Harrison alongside Darrell Arthur on October 15.
Chicago Bulls (2018–present)
On October 21, 2018, Harrison was signed by the Chicago Bulls, replacing the spot previously held by Ömer Aşık. On July 6, 2019, Harrison was waived by the Bulls along with Walt Lemon Jr., but later on July 18, 2019, the Chicago Bulls signed Harrison again.
NBA career statistics
Regular season
Personal life
Harrison was born to Jack and Michelle Harrison, with his father dying in the second grade due to a heart attack. He also has two brothers and a sister. His younger brother, Monte Harrison, currently plays for the Miami Marlins of Major League Baseball. Harrison's playing style has a focus primarily on the defensive end, having a serious interest on that end of the game since the fourth grade.
