Born in New York City. He began staging amateur shows in Denver while still in high school. He started his professional career in a minstrel show. After several years in New York vaudeville, he entered films around 1915, producing independently. In 1919 he went to work for the Selznick company and in 1921 joined Warner Bros., for whom he discovered Rin Tin Tin and produced the popular dog's profitable movies. In 1921 he joined the newly merged MGM where he became one of the studio's top triumvirate, sharing producing responsibility with Irving Thalberg and Louis B. Mayer. He was assigned to the "program pictures," the run-of-the-mill movie output, personally producing some of these films. He was credited with discovering Joan Crawford and other major stars, as well as important directors and writers who started their careers under his guidance. Rapf was one of the 36 founders of the Academy of Motion Picture Arts and Sciences.  Production 1928-29: BROADWAY MELODY, Producer  Nominated for Production 1928-29: THE HOLLYWOOD REVUE OF 1929, Producer 2 nominations, 1 Award