His first film appearance was in Kelly the Second (1936), followed by Dark Manhattan (1937). His other film credits include The Jackie Robinson Story (1950), Carmen Jones (1954), Porgy and Bess (1959), The Sound and the Fury (1959), A Raisin in the Sun (1961), with Sidney Poitier, Ruby Dee and Claudia McNeil, and a memorable turn as Mr. Prentice (again playing opposite Poitier) in the 1967 film Guess Who's Coming to Dinner. Roy Glenn's last big screen appearance was in Support Your Local Gunfighter (1971).