Gregory Neale Harrison (born May 31, 1950 in Avalon, Santa Catalina Island, California) is an American actor. He is probably best known for his role as Chandler in the 1987 cult favorite North Shore and as Pernell Roberts's young surgeon, Dr. George Alonzo 'Gonzo' Gates, on the CBS series Trapper John, M.D. (a role he played from 1979 to 1985). He was also the title character on the 1977-78 science fiction series Logan's Run, after which he played the role of Levi Zendt on the 1978 NBC miniseries Centennial and had a situation comedy on CBS called Family Man, in which he played a single-father fireman who was rearing three children. He also played a widowed sheriff rearing three children in his mother's motel called Safe Harbor (1999)..