By age 14 he was already appearing in Universal Studio’s Joker films. From 1915 to 1916 he co-starred in a series of shorts with Gloria Swanson. In 1917, Mack Sennett opted not to renew his contract, and Vernon went over to the Christie Film Company, becoming one of their biggest comedy stars until the studio switched over to talkies in 1928. He continued to act in shorts for various studios until 1932, at which time he became a screenwriter and comedy supervisor for Paramount until he died of a heart attack at age 42.
For more on the history of silent and slapstick comedy please see Chain of Fools: Silent Comedy and Its Legacies from Nickelodeons to Youtube, just released by Bear Manor Media, also available from amazon.com etc etc etc