Harry Crocker was born in San Francisco, Calif., the son of Henry J. Crocker and grandson of Charles Crocker. He went to Hollywood in 1924, where he met Marion Davies. Davies introduced him to Charlie Chaplin, and the two became friends. Crocker was Chaplin's assistant director on the motion picture The circus (United Artists, 1928) and also appeared in the film as Rex, the tightrope walker.
From the description of Harry Crocker materials pertaining to Charlie Chaplin and The circus, 1925-1929 (bulk n.d.). (California Historical Society). WorldCat record id: 145415622