Gary Grimes' first major role was in the 1971 motion picture Summer of '42, playing a teenager who has an affair with a beautiful older woman, played by Jennifer O'Neill. For that role, Grimes was nominated in 1972 for a Golden Globe Award as Most Promising Newcomer, as well as the Male and a BAFTA Award as Best Newcomer.
Grimes also starred in the sequelClass of '44 (1973), which followed his character to college.
Grimes retired from show business in the late 1970s, still lives in Los Angeles and has remained out of public view since that time. "I got to the point where the work wasn't up to the quality that I wanted," Grimes told American Profile magazine in 2011. "I'm very happy in my decision."