He made his Broadway debut as the lead in Emlyn Williams' The Morning Star in 1942. His second Broadway performance that year was in The Willow and I with Edward Pawley. Peck's acting abilities were in high demand during World War II, since he was exempt from military service owing to a back injury suffered while receiving dance and movement lessons from Martha Graham as part of his acting training. Twentieth Century Fox claimed he had injured his back while rowing at university, but in Peck's words, "In Hollywood, they didn't think a dance class was macho enough, I guess. I've been trying to straighten out that story for years."
In 1949, Peck founded The La Jolla Playhouse, at his birthplace, along with his friends Jose Ferrer and Dorothy McGuire. This local community theater and landmark still thrives today. It has attracted Hollywood film stars on hiatus both as performers and enthusiastic supporters since its inception.
Peck's first film, Days of Glory, was released in 1944. He was nominated for the Academy Award for Best Actor five times, four of which came in his first five years of film acting: for The Keys of the Kingdom (1944), The Yearling (1946), Gentleman's Agreement (1947), and Twelve O'Clock High (1949).
The Keys of the Kingdom emphasized his stately presence. As the farmer Penny Barker in The Yearling his good-humored warmth and affection toward the characters playing his son and wife confounded critics who had been insisting he was a lifeless performer. Duel in the Sun (1946) showed his range as an actor in his first "against type" role as a cruel, libidinous gunslinger. Gentleman's Agreement established his power in the "social conscience" genre in a film that took on the deep-seated but subtle anti-Semitism of mid-century corporate America. Twelve O'Clock High was the first of many successful war films in which Peck embodied the brave, effective, yet human fighting man.
Among his other popular films were "The Gunfighter" 1950, Moby Dick (1956), On the Beach (1959), which brought to life the terrors of global nuclear war, The Guns of Navarone (1961), and Roman Holiday (1953), with Audrey Hepburn in her Oscar-winning role. Peck and Hepburn were close friends until her death; Peck even introduced her to her first husband, Mel Ferrer. Peck once again teamed up with director William Wyler in the epic Western "The Big Country" (1958), which he co-produced.
Peck won the Academy award with his fifth nomination, playing Atticus Finch, a Depression-era lawyer and widowed father, in a film adaptation of the Harper Lee novel To Kill a Mockingbird. Released in 1962 during the height of the US civil rights movement in the South, this movie and his role were Peck's favorites.
He served as the president of the Academy of Motion Picture Arts and Sciences in 1967, Chairman of the Board of Trustees of the American Film Institute from 1967 to 1969, Chairman of the Motion Picture and Television Relief Fund in 1971, and National Chairman of the American Cancer Society in 1966. He was a member of the National Council on the Arts from 1964 to 1966.
A physically powerful man, he was known to do a majority of his own fight scenes, rarely using body or stunt doubles. In fact, Robert Mitchum, his on-screen opponent in Cape Fear, often said that Peck once accidentally punched him for real during their final fight scene in the movie.
Peck's rare attempts at unsympathetic roles usually failed. He played the renegade son in the Western Duel in the Sun and the infamous Nazi doctor Josef Mengele in The Boys from Brazil. Critics could be unkind. Pauline Kael of the New Yorker once labeled Peck "competent but always a little boring." He famously did not get along with Marlon Brando, who described him as "a wooden actor and a pompous individual". Off-screen as well as on Peck conveyed a quiet dignity, He had one amicable divorce, and scandal never touched him.
In the 1980s, Peck moved to television, where he starred in the mini-series The Blue and the Gray, playing Abraham Lincoln. He also starred with Barbara Bouchet in the Television film The Scarlet and The Black, about a real-life Roman Catholic priest in the Vatican who smuggled Jews and other refugees away from the Nazis during World War II.
Gregory Peck, Robert Mitchum and Martin Balsam all had roles in the 1991 remake of Cape Fear directed by Martin Scorsese. All three were in the original 1962 version. In the remake, Peck plays Max Cady's lawyer.
Peck retired from active film-making in 1991. Like Cary Grant before him, Peck spent the last few years of his life touring the world doing speaking engagements in which he would show clips from his movies, reminisce, and answer questions from the audience. He came out of retirement to appear in the 1998 remake of one of his most famous films, Moby Dick, portraying Father Mapple, with Patrick Stewart as Captain Ahab, the role Peck played in the earlier film.
On June 12, 2003, Peck died in his sleep from cardiorespiratory arrest, and bronchial pneumonia, age 87, at Torrance Memorial Medical Center in Torrance, California. His wife of 48 years was at his side.