With the advent of sound drastically changing and curtailing the two-reel comedy format, St. John diversified, creating a second career for himself as a comic sidekick in Western films and ultimately developing the character of "Fuzzy Q. Jones", for which he is best known in posterity.
St. John made more than 80 western films in this character, which proved indispensable to the PRC studio and so popular that "Fuzzy Settles Down" (1944) remains the only American B-Western that is titled after the sidekick.
These films had, in many cases, multiple theatrical distributors, and most of the PRCs were re-released in the 1950s by Madison Pictures, though in some instances in cut down versions.
When Arbuckle left Keystone in early 1917 to form the Comique Comedy unit at Paramount, he and St. John were joined by stage comedian Buster Keaton, and the three created a singular cycle of silent comedies that exploited their matched acrobatic abilities and hard-driving capabilities in slapstick.
This list may be incomplete, as the full extent of St. John's appearances of this kind is not known, owing to so many lost films that may serve as possible candidates.
Some of these, particularly his serio-comic turn as "Uncle Billy" in The Outcasts of Poker Flat (1937), demonstrate a greater range of acting ability than the average Fuzzy Q. Jones role might suggest.