What was Robert Duvall’s film debut? August 2, 2020 by Pamela Landy Robert Duvall’s film debut was Boo Radley in To Kill a Mockingbird (1962). Related Answers What was the first film in which Andy Hardy appeared? What was the first all-black sitcom on TV? What was Robert Redford’s directorial debut? What was the feature film debut of radio’s “Amos n Andy”? What was Bette Davis’s film debut? What was Katharine Hepburn’s film debut?