He made his acting debut at the age of 10 in Richmond, Virginia, in a production of Julius Caesar, with Edwin Booth playing the title character.

[2] In The Spoilers in 1914, Farnum and Tom Santschi staged a film fight which lasted for a full reel.

In 1930, Farnum and Santschi coached Gary Cooper and William Boyd in the fight scene for the 1930 version of The Spoilers.

Other actors influenced by the Farnum/Santschi scene were Milton Sills and Noah Beery in 1923 and Randolph Scott and John Wayne in 1942.

[citation needed] Farnum's silent pictures Drag Harlan (1920) and If I Were King (1921) survive from his years contracted to Fox Films.