Douglas Kennedy was a character player and occasional leading man in Hollywood. He attended Deerfield Academy in Deerfield, Massachusetts, and afterwards graduated from Amherst College in Amherst, Massachusetts. Making his debut in 1935, he played a significant number of supporting roles and was able to secure contract-player status, first at Paramount Pictures and later at Warner Brothers. His acting career was interrupted by World War II service as a major in the Signal Corps with the Office of Strategic Services and Army Intelligence. After that, he returned to films and played character roles, often western villains or territorial marshals, as well as isolated leads in low-budget pictures. Kennedy had a starring role in the syndicated series Steve Donovan, Western Marshal, with Eddy Waller as his sidekick, Rusty Lee. He was also one of the policemen who vanishes in the science fiction classic, Invaders from Mars. He played the gunfighter William P. Longley in a 1954 episode of the syndicated television series Stories of the Century, starring and narrated by Jim Davis.

In 1958, Douglas Kennedy appeared in Jim Davis’ second series, Rescue 8 in the episode “Calamity Coach”. In the story line, rescuers Wes Cameron (Davis) and Skip Johnson (Lang Jeffries) work to rescue three actors on location when a stagecoach tumbles down a mountain. On January 12, 1959, Kennedy appeared in the episode “Shadow of a Gunfighter” of the NBC western series The Restless Gun. He plays a former gunfighter, Cal Winfield, who is informed that Vint Bonner, (John Payne), is responsible for the death of Winfield’s son. Cal Winfield then comes out of retirement to extract vengeance. Robert Fuller appears in the episode as Jim Winfield. Kennedy played the role of Jay Brisco in the 1959 episode “Law West of the Pecos” of the ABC/Warner Brothers western series, Colt .45. Frank Ferguson portrayed Judge Roy Bean, and Lisa Gaye was cast as June Webster. Later, Kennedy portrayed the sheriff, Fred Madden, of ABC’s The Big Valley, with Barbara Stanwyck. He made his last appearance in 1973 in three episodes of CBS’s Hawaii Five-O, with Jack Lord. Kennedy died of cancer at the age of fifty-seven in Honolulu, Hawaii, where he had been for the shooting of Hawaii Five-O. He is interred at National Memorial Cemetery of the Pacific in Honolulu.