Begley began his career as a
Broadway and radio actor while in his teens. He appeared in the hit musical
Going Up on Broadway in 1917 and in London the next year. He later acted in roles as Sgt. O'Hara in the radio show
The Fat Man. His radio work included
Stroke of Fate and a period as
Charlie Chan, among other roles. He also starred in the 1950s radio program
Richard Diamond, Private Detective, playing Lieutenant Walter Levinson, head of homicide at the 5th Precinct, Manhattan. He was elected a member of
The Lambs in 1943. In the late 1940s, he began appearing regularly in supporting film roles. in 1969 In the 1952–1953
television season, Begley co-starred with
Eddie Albert in the
CBS sitcom Leave It to Larry. In 1954 Begley starred in the
NBC Television show
Robert Montgomery Presents in "Big Boy", an episode sponsored by
Lucky Strike, as Joe Grant, an engineer for the
Union Pacific Railroad living in
Cheyenne, Wyoming, who worked on the famous
Union Pacific Big Boy steam locomotives. The show is about how Begley's character copes with the
transition from
steam locomotives to
diesel locomotives in the 1950s. He won the
Academy Award for Best Supporting Actor for his role in
Sweet Bird of Youth (1962). Some of his other notable films include
Deadline – U.S.A. (1952),
12 Angry Men (1957) as juror #10,
Odds Against Tomorrow (1959),
The Unsinkable Molly Brown (1964), and
Wild in the Streets (1968). One notable role Begley played both on television (twice in
1955) and in the theatrical film (1956) is William (Bill) Briggs, one of the three primary characters in
Rod Serling's
Patterns. In 1956, he appeared in the Broadway production of
Inherit the Wind, in the role of Matthew Harrison Brady. For this performance, he won the
Tony Award for
Best Featured Actor in a Play. In 1968 he appeared with Clint Eastwood in the classic Western ''
Hang 'Em High''. His other television work included appearances on the 1954 TV series
Justice,
Empire,
The Virginian,
Bonanza,
The Fugitive,
The Dick Van Dyke Show,
Target: The Corruptors,
The Invaders,
The Wild Wild West,
My Three Sons,
Wagon Train and
Going My Way, with
Gene Kelly. Among his many Broadway credits were
All My Sons and
Our Town. ==Personal life==