Ladd was born in Hot Springs, Arkansas. He was the only child of Ina Raleigh Ladd and Alan Ladd, Sr. He was of English ancestry. His father died when he was four, and his mother relocated to Oklahoma City where she married Jim Beavers, a housepainter. The family then moved again to North Hollywood, California where Ladd became a high-school swimming and diving champion and participated in high school dramatics at North Hollywood High School, graduating on February 1, 1934. He opened his own hamburger and malt shop, which he called Tiny's Patio. He worked briefly as a studio carpenter (as did his stepfather) and for a short time was part of the Universal Pictures studio school for actors. But Universal decided he was too blond and too short and dropped him.
Intent on acting, he found work in small theatres. He had short term stints at MGM and RKO, and eventually started getting steady work on radio. Ladd was heard on radio by the agent Sue Carol who signed him to her books and enthusiastically promoted her new client, starting with Rulers of the Sea.
Ladd began by appearing in dozens of films in small roles, including Citizen Kane in which he played one of the "faceless" reporters who are always shown in silhouette. He first gained some wide recognition with a featured role in the wartime thriller Joan of Paris, 1942. For his next role, Sue Carol, found a vehicle which made Ladd's career, Graham Greene's This Gun for Hire in which he played "Raven," a hitman with a conscience. "Once Ladd had acquired an unsmiling hardness, he was transformed from an extra to a phenomenon. Ladd's calm slender ferocity make it clear that he was the first American actor to show the killer as a cold angel." – David Thomson (A Biographical Dictionary of Film, 1975)
Both the film and Ladd's performance played an important role in the development of the "gangster" genre: "That the old fashioned motion picture gangster with his ugly face, gaudy cars, and flashy clothes was replaced by a smoother, better looking, and better dressed bad man was largely the work of Mr. Ladd." – New York Times obituary (January 30, 1964).
Ladd was teamed with actress Veronica Lake in this film, and despite the fact that it was Robert Preston who played the romantic lead, the Ladd-Lake pairing captured the public's imagination, and would continue in another three films. (They appeared in a total of seven films together, but three were only guest shots in all-star musical revues.) Ladd went on to star in many Paramount Pictures' films, with a brief timeout for military service in the United States Army Air Forces First Motion Picture Unit. He appeared in Dashiell Hammett's story The Glass Key, his second pairing with Lake, and Lucky Jordan with Helen Walker. His cool, unsmiling persona proved popular with wartime audiences, and he was quickly established as one of the top box office stars of the decade.
In 1946, he starred in a trio of silver screen classics: the big screen adaptation of Richard Henry Dana's maritime classic, Two Years Before the Mast (for which he also received critical acclaim), the Raymond Chandler original mystery The Blue Dahlia (his third pairing with Lake), and the World War II espionage thriller O.S.S.. He formed his own production companies for film and radio and then starred in his own syndicated series Box 13, which ran from 1948–49. Ladd and Robert Preston starred in the 1948 western film, Whispering Smith, which in 1961 would become a short-lived NBC television series, starring Audie Murphy. In the 1949 version of The Great Gatsby, Ladd had the featured role of Jay Gatsby.
Jean Arthur and Alan Ladd in Shane(1953)
Ladd played the title role in the 1953 western Shane. The film was nominated for five Academy Awards, including Best Picture. It was listed at No. 45 on the American Film Institute's 2007 ranking of "100 Years ... 100 Movies." Ladd made the Top Ten Money Making Stars Poll three times: in 1947, 1953, and 1954. In 1954 exhibitors voted him the most popular star among British film-goers.
When former agent Albert R. Broccoli formed Warwick Films with his partner Irving Allen, they heard Ladd was unhappy with Paramount and was leaving the studio. With his wife and agent Sue Carol, they negotiated for Ladd to appear in the first three of their films made in England and released through Columbia Pictures: The Red Beret/Paratrooper (1953); Hell Below Zero (1954), based on Hammond Innes's book The White South; and The Black Knight(1954). All three were co-written by Ladd's regular screenwriter Richard Maibaum.
In 1954 Ladd formed a new production company, Jaguar Productions, originally releasing his films through Warner Bros. and then with All the Young Men through Columbia. Ladd's pictures became less distinguished as the decade went on. He turned down the chance to appear in the role of Jett Rink in Giant (1956) which was subsequently played by James Dean and became one of the biggest hits of the decade.
In November 1962, he was found lying unconscious in a pool of blood with a bullet wound near his heart, in what might have been an unsuccessful suicide attempt. In 1963 Ladd's career looked set to make a comeback when he filmed a supporting role in The Carpetbaggers, which became one of the most popular films of 1964. He would not live to see its release.
On January 29, 1964 he was found dead in Palm Springs, California, of an acute overdose of "alcohol and three other drugs", at the age of 50; his death was ruled accidental. Ladd suffered from chronicinsomnia and regularly used sleeping pills and alcohol. It was determined that he had not taken a lethal amount of either, but that the combination can produce a synergistic reaction in which "one plus one equals ten or even fifty. He was entombed in the Forest Lawn Memorial Park Cemetery in Glendale, California.
Ladd has a star on the Hollywood Walk of Fame at 1601 Vine Street. His handprint appears in the forecourt of Grauman's Chinese Theater, in Hollywood. In 1995, a Golden Palm Star on the Palm Springs, California, Walk of Stars was dedicated to him.