Harris' first film role came in 1978 with a minor part in the suspense film "Coma", starring Michael Douglas. His first major role in a film came two years later with "Borderline" (1980), in which he starred alongside Charles Bronson. In 1981, Harris played the lead, William "Billy" Davis, a king of a motorcycle riding renaissance-fair troupe (a role modeled after King Arthur), in "Knightriders", directed by George A. Romero. The following year, he has a small role as Hank Blaine in "Creepshow", also directed by Romero.