Marc Sheffler used to work as a stage actor for off-Broadway theater. His only film role is of the teenage Junior Stillo in the low-budget Last House on the Left (1972). Since then, Sheffler decided to pursue a career into television writing and production rather than acting.
His credits include episodes of "Sister, Sister", "Harry and the Hendersons", "Who's the Boss", and "Charles in Charge" to name but a few. He's also been involved with all kinds of pilots, made for TV movies, and television specials, including the failed "The Little Shop of Horrors" pilot, "The Happy Days Reunion Show" and "The Best of the Hollywood Palace" specials. He also worked with Mel Blanc, the voice of Warner Bros. cartoons, as the writer of How Bugs Bunny Won The West (1978).