He often worked with actor William Bendix; they had prominent roles in the 1946 film noir The Blue Dahlia, playing the friends of star Alan Ladd's character.

In 1946–1947, Beaumont starred in five films as private detective Michael Shayne, assuming the role from Lloyd Nolan.

From 1951 to 1953, he narrated the Reed Hadley series Racket Squad, based on the cases of fictional detective Captain John Braddock in San Francisco.

[8] He also continued to have success as a writer, selling several television screenplays and radio scripts as well as short stories to various magazines.

[12] He gradually left the entertainment business, launching a second career as a Christmas-tree farmer in Grand Rapids, Minnesota.

On April 13, 1941, Beaumont wed actress Kathryn Adams (née Hohn) at the Hollywood Congregational Church.

[8][16] On May 14, 1982, Beaumont died of a heart attack while visiting his son Hunter, a psychologist, in Munich, West Germany.