Grimsby returned to his native Duluth, Minnesota, where he began his anchoring career in 1954, serving as an announcer for WEBC Radio. Shortly thereafter, he decided to switch to the growing medium of television, working as a correspondent and news director at various television stations around Minnesota and Wisconsin, including WEAU-TVEau Claire, WISC-TVMadison, and WXIX-TV Milwaukee. He then spent two years at KMOX in St. Louis, before becoming the anchor and news director at ABC-owned KGO-TV in San Francisco, in 1961. In 1968 Grimsby was brought to WABC-TV in New York City. Grimsby started as anchor of WABC's 11:00 p.m. news broadcast, Roger Grimsby and the Noisemakers, on June 3, 1968. Just two days later, Grimsby was thrust into the national spotlight as anchor of ABC's coverage of the assassination of Robert F. Kennedy. In April 1969, WABC dropped John Schubeck from the anchor slot on their 6:00 p.m. broadcast, replacing him with Grimsby, who also continued in the 11:00 p.m. slot. Grimsby's initial co-anchor on the 6:00 newscast was former WCBS-TV newsman Tom Dunn, but the man who was most closely identified with him was Bill Beutel, who replaced Dunn in September 1970 and co-anchored the news with Grimsby until 1986. He started each broadcast announcing, "Good evening, I’m Roger Grimsby, here now the news." A six-time Emmy Winner, Grimsby was fired from WABC in April 1986 and, in an incident recounted by several of his colleagues, including Tom Snyder, ABC further punished Grimsby by buying a building on Columbus Avenue across from WABC's Lincoln Square studios where three bars Grimsby often frequented stood and evicting the bar owners from the building. A year after his WABC departure, Grimsby was hired by WNBC-TV in May 1987. Beginning in June, his role was almost exclusively as a commentator, as Grimsby would be featured as part of the station's daily Live at Five newscast in a brief segment where he offered his take on a news story of the day with his usual deadpan style. He also worked as an assignment reporter. When WNBC's corporate sibling, WNBC, signed off the air in 1988, Grimsby was dispatched to the radio station's studio to cover the closure live. As it turned out, a late transmitter switch to WFAN meant that Grimsby's voice was the very last to be heard on WNBC AM as he declared live to TV viewers: You heard the countdown. It's over. Grimsby left WNBC in May 1989 when his contract was not renewed. In 1990, he relocated to California where he and George Reading of KMST became the first anchor team on San Diego television station KUSI's newly-launched 10:00 p.m. newscast. After only a few months, Grimsby resigned from KUSI in February 1991.
Death
After his retirement, Grimsby returned to New York City and lived on Manhattan's Upper West Side with his wife Maria, whom he had married in 1989. On June 23, 1995, Grimsby died in Lenox Hill Hospital from complications due to advanced lung cancer.
