William Gargan was an American actor, better known for playing fictional detectives Ellery Queen, Martin Kane, and Barrie Craig. He was once nominated for the Academy Award for Best Supporting Actor.

Gargan was born and raised in Brooklyn, New York City. He attended St. James School in Brooklyn. While he was the younger brother of actor Edward Gargan (1902-1964), Gargan was not initially interested in an acting career. He worked as a salesman of bootleg whiskey during the Prohibition, and later as a professional detective. His life changed through a visit to his brother on a musical comedy stage/ Gargan was offered a stage job of his own, and he accepted.

Gargan started out as a theatrical actor, appearing in the play "Aloma of the South Seas". His film career started in the 1930s, and he was often typecast as as a stereotypical Irishman. He played policemen, priests, reporters, and adventurers. He was nominated for the Academy Award for Best Supporting Actor for his role as Joe in the romantic drama "They Knew What They Wanted" (1940). The film was an adaptation of a 1924 play by Sidney Howard (1891-1939), and Joe was depicted as a womanizing foreman who has an affair with a woman engaged to one of his workers. While Gargan's role was critically well-received, the award was instead won by rival actor Walter Brennan (1894-1974).

In the 1940s, Gargan portrayed popular detective Ellery Queen in three films: "A Close Call for Ellery Queen" (1942), "A Desperate Chance for Ellery Queen" (1942), and "Enemy Agents Meet Ellery Queen" (1942). "Enemy Agents" was the final entry in the Ellery Queen film series. Gargan spend the rest of the decade mostly playing supporting roles in film.

Gargan found another major role as a detective, playing protagonist Martin Kane in the radio series "Martin Kane, Private Eye".(1949-1952). He also appeared in the television adaptation of the series, which lasted from 1949 to 1954. While he was the originator of the role, Gargan was eventually replaced by actor Lloyd Nolan (1902-1985). Nolan was eventually replaced by actor Lee Tracy (1898-1968). The final actor to portray Martin Kane in the original series was Mark Stevens (1916-1994). Gargan returned to the role in the sequel series "The New Adventures of Martin Kane" (1957).

Gargan also played detective Barrie Craig in the popular radio series "Barrie Craig, Confidential Investigator" (1951-1955). Unlike the hard-boiled detectives of the genre (popularized by Sam Spade and Philip Marlowe), Craig was noted for his laid-back personality. The series was suggested for adaptation to a television series, but only an unsuccessful pilot episode was filmed.

Gargan's acting career ended abruptly in 1958, when he was diagnosed with throat cancer. His larynx was surgically removed in 1960. This saved his life, but Gargan lost his distinctive voice. He spend the rest of his life speaking through an artificial voice box. He became a spokesman for the American Cancer Society, warning people about the dangers of smoking. Meanwhile he established his own production company, William Gargan Productions.

In 1979, Gargan suffered a mid-flight heart attack, while flying from New York City to San Diego. He died due to the heart attack, at the age of 73. He was buried at Holy Cross Cemetery in San Diego, California.