According to Massachusetts birth registries and federal census records, Mitchell supported his family as a "cutter" in shoemaking factories.

In a 1965 interview with The Berkshire Eagle, a newspaper in his home state, he shared his views on how military service had affected him personally, especially his difficulties in readjusting to civilian life:What was my hangup then?

[4]After his lead role in the radio serial Captain Starr of Space during the broadcast season of 1953–1954,[5] he began to perform increasingly in films.

He was usually cast on the "big screen" in Westerns (How The West Was Won, 1962) and in other action films outside that genre, including Miracle of the White Stallions as General George S. Patton Jr. (1963), the television film Collision Course: Truman vs. MacArthur as General Omar Bradley (1976), and replacing James Gregory as Mac in the Matt Helm movie The Wrecking Crew (1969) starring Dean Martin, Sharon Tate, and Elke Sommer.

Larch, for example, appears with her in the 1968 episode "Yesterday Died and Tomorrow Won't Be Born" on the CBS weekly crime drama Hawaii Five-O starring Jack Lord.

He is interred in a wall crypt at Mount Sinai Memorial Park in nearby Hollywood Hills.