Beaumont began his career in show business in 1931 by performing in theaters, nightclubs, and radio. He began acting in motion pictures in 1940, appearing in over three dozen films. Many of those roles were bit parts and minor roles and were not credited. 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. In 1950, he narrated the short film
A Date with Your Family. He also starred in
The Mole People in 1956. In the early 1950s, Beaumont secured television work, often with guest roles on series such as
Adventures of Superman,
City Detective,
Crossroads,
Fireside Theatre,
Ford Theatre,
The Lone Ranger,
Medic,
The Millionaire, and
Schlitz Playhouse of Stars. 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. In 1954 and 1955, Beaumont appeared in
The Public Defender, Hadley's second series, appearing in three episodes as Ed McGrath. That year, he guest-starred in the
Lassie episode "The Well", one of two episodes filmed as pilots for the series. In 1959, before production on the third season of
Leave It to Beaver began, Beaumont's wife, son, and mother-in-law were driving from Minnesota to Hollywood to visit when a car accident killed Beaumont's mother-in-law and severely injured his son.
Jerry Mathers later stated that the tragedy seriously affected Beaumont's participation in the production, with Beaumont often just "walking through" his part. After
Leave It to Beaver ended production in 1963, Beaumont appeared in many community theater productions and played a few guest roles on television series such as
Marcus Welby, M.D.,
Mannix,
Petticoat Junction,
The Virginian, and
Wagon Train. In February 1966, he made another appearance on
Lassie, 11 years after his first. He gradually left the entertainment business, launching a second career as a Christmas-tree farmer in Grand Rapids, Minnesota. After suffering a debilitating stroke in 1970, Beaumont officially retired from acting in 1972. In 1980, he did appear in a
Beaver reunion with the rest of the cast that was conducted by a local Los Angeles TV station. ==Personal life and death==