Before entering show business, he was a cartoonist for The Brooklyn Eagle newspaper.
In scores of short films, Semon rivaled Charles Chaplin in comic popularity during the early 1920s. He directed The Wizard of Oz (1925), one of his very few feature-length films, in which he played the Scarecrow with Oliver Hardy as the Tin Man. He married his leading lady, Dorothy Dwan, who played Dorothy, just before the film's release. Unfortunately, it was not a success and effectively killed Semon's career, which was already on the skids. He died a few years later.
Semon taught Oliver Hardy to play golf. Hardy became one of the best golfers in Hollywood.
Son of vaudeville comedian Zera the Great.
The somewhat mysterious circumstances surrounding his death have led some to believe that he faked his own demise.