His film career successfully transitioned from the silent era into sound, and by the late 1930s and 1940s he was working predominantly in Westerns, often portraying the scruffy comedy-relief character "Fuzzy Q.

"[8] When Arbuckle formed his own production company, he brought St. John with him and recruited stage star Buster Keaton into his films, creating a formidable roughhouse trio.

[9] After Arbuckle was involved in a widely publicized scandal that prevented him from appearing in movies, he pseudonymously directed his nephew Al as a comic leading man in silent and sound films such as The Iron Mule (1925) and Bridge Wives (1932).

He appears, for example, in this type of role in Buster Keaton's 1937 comedy short Love Nest on Wheels, portraying the hillbilly character Uncle Jed.

[10] That same year he began supporting cowboy stars Fred Scott and later Jack Randall, but most of his films were made for Poverty Row studio Producers Releasing Corporation (PRC).

When Crabbe left PRC (according to interviews, in disgust at the productions' increasingly low budgets), St. John was paired with new star Lash LaRue.

According to his obituaries, he suffered a massive heart attack at a motel in Lyons, Georgia, as he prepared for a special appearance at a nearby American Legion club.