Gregory Neale Harrison was born on May 31, 1950 in Avalon, Catalina Island, California. After HS he served in the United States Army during the Vietnam War as a medic for two years. After two years he received an honorable discharge in 1971 from the Army as a non-religious conscientious objector.
After the army he began working as a doorman for a nightclub. One night while working he met actor Jason Robards who took notice of the young man, and encouraged him to get into acting, as he had the looks for television. Harrison took the words of encouragement as a sign and quit his job and moved to LA immediately. He began taking acting lessons as well as vocal and dance, and began working in theatre and musical theatre. In 1973 he booked his first job, as one of the students in “The Harrad Experiment”, an uncredited extra role. In 1975 he booked his first speaking role, with a role in “Trilogy of Terror”. He would do another film and a few guest spots on television, but it was him landing a guest spot on the super-hit series “MASH” in 1976 that would help him get more steady work.
After appearing in one episode of “MASH” in 1976 he was cast in a role in the film “Fraternity Row” and then a supporting role in the TV film “The Gathering” in 1977. After that he was cast as the lead of the TV series “Logan’s Run” that same year. The series only lasted 14 episodes before being canceled in early 1978.
In 1978 he was cast in a supporting role in the hit mini-series “Centennial”. In 1979 he would land the role that would be his most successful, one of the lead roles of the hit CBS series “Trapper John, MD”. The series was a spinoff of MASH. He would star in that series for over 6 years, leaving midway through season 7. While on the show he starred in numerous television films, but most notably he was the lead of the tv movie “For Ladies Only” in 1981, a tv movie about a man from Iowa who moves to NYC to become an actor but becomes a stripper to make money when he goes broke. The film gave him a huge following with women and gay men. In 1986 he starred in the miniseries “Fresno”, playing a character that spoofed his character in “For Ladies Only”.
After “Trapper John, MD” he did more small films and tv movie before jointing “Falcon Crest” in 1989, in what would be its final season. In 1990 he starred in his own sitcom “The Family Man”, which was canceled after one season despite CBS trying to build it an audience. Throughout the 90s and 00s he would star in many tv movies and do many guest spots on tv shows. In 1994 he joined the series “Sisters” for one season.
In 2020 he joined the cast of General Hospital as Gregory Chase.
He played Billy Flynn in a touring production of Chicago, and he was the male lead in each film of the Au Pair trilogy. He also appeared as Benjamin Stone in the Broadway revival of Stephen Sondheim's Follies and starred in the original Broadway production of Kander & Ebb's musical Steel Pier.
He has been married for over 40 years and has three daughters and one son via adoption.
In the 80s he fell deep into alcoholism and became a cocaine addict. He entered himself into the Betty Ford Center for help.