He was best known for the roles of Major Harvey Stovall in Twelve O'Clock High (1964-1967), Sheriff Heck Tate in To Kill a Mockingbird (1962), and General Bogan in Fail Safe (1964).

[2] His Broadway credits include The Desperate Hours (1954), The Trip to Bountiful (1953), Truckline Cafe (1945), and Jacobowsky and the Colonel (1943).

He played the father of Joe's terminally ill fiancee (Brooke Hayward) in Bonanza Season 3 Episode 19 "The Storm" which aired on 1/27/1962.

Overton also played a significant role in the movie Wild River, where he appeared as the jilted fiancé of Lee Remick.

One of his last TV roles was that of Elias Sandoval in Star Trek's "This Side of Paradise", which originally aired in March 1967, just one month before his death at age 49.