<Li> John Qualen as Berger, Laszlo's Resistance contact . He was born in Canada, but grew up in the United States . He appeared in many of John Ford's films . </Li> <Li> S.Z. Sakall (credited as S.K. Sakall) as Carl, the waiter . The Jewish - Hungarian actor fled Germany in 1939 . His three sisters later died in a concentration camp . </Li> <Li> Dooley Wilson as Sam . He was one of the few American - born members of the cast . A drummer, he had to fake playing the piano . Even after shooting had been completed, producer Wallis considered dubbing over Wilson's voice for the songs . He had originally considered changing the character to a woman and casting singers Hazel Scott, Lena Horne, or Ella Fitzgerald . </Li> <P> Notable uncredited actors are: </P>

Who played the pianist sam of play it again sam theme in the movie casablanca