[2][3] His father, a native of Italy, immigrated to the United States in 1901 and lived in Pennsylvania before moving to California, where by 1930 he was employed as a waiter in a Los Angeles cafe.

[3][4] To supplement his family's modest income, Devon later worked part-time as a stable boy and then as a riding instructor at an equestrian academy in Griffith Park.

Following his graduation from high school, Devon worked as a mail carrier at Monogram Pictures, a laborer at a plant nursery, a mechanic's helper, and as a doorman at the Hollywood Palladium.

He guest-starred on several episodes of The Rifleman from 1959 to 1962: "Blood Brother"[6] as Jethroe, "The Spiked Rifle"[7] as Stark, "The Grasshopper"[8] as Ryerson, "The Silent Knife"[9] as Macowan, "Miss Milly"[10] as Adams, "The Stand-In"[11] as Potter and "The Most Amazing Man"[12] as Lovett.

Devon had a regular role as well as on the CBS series Yancy Derringer, performing the part of Jody Barker, a pickpocket and sometime cohort of the lead character played by Jock Mahoney.