His father was a traveling salesman and ventriloquist and Duncan joined his act at age 6.

[1] Although his father sent him to a military school, Duncan started taking on more acting roles after graduation and eventually ended up in vaudeville.

[3] Shortly after the Mutt and Jeff series ended, Duncan returned to vaudeville, where he first encountered Lloyd Hamilton.

[2] He and Hamilton were hired by the Kalem Company for a series of one-reelers as the comedy duo, Ham and Bud.

Duncan was mainly limited to bit roles during the sound era and he largely retired from films in the early 1930s.