In the 1960s, he became noted for supporting roles, perhaps most memorably as General Jack D. Ripper in Kubrick's Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb (1964).

Hayden's success continued into the New Hollywood era, with roles such as Irish-American policeman Captain McCluskey in Francis Ford Coppola's The Godfather (1972), alcoholic novelist Roger Wade in Robert Altman's The Long Goodbye (1973), elderly peasant Leo Dalcò in Bernardo Bertolucci's 1900 (1976), and chairman of the board Russell Tinsworthy in 9 to 5 (1980).

With a distinctive "rapid-fire baritone" voice and an imposing stature at 6 ft 5 in (196 cm),[1][2] he had a commanding screen presence in both leading and supporting roles.

[6] Later, he was a fisherman on the Grand Banks of Newfoundland, ran a charter yacht, and served as a fireman on 11 trips to Cuba aboard a steamer.

[6] He skippered a trading schooner in the Caribbean after earning his master's license, and in 1937 he served as mate on a world cruise of the brigantine Yankee.

[6] After working as a sailor and fireman on larger vessels and sailing around the world several times, he was awarded his first command at age 22, skippering the square rigger Florence C. Robinson 7,700 miles from Gloucester, Massachusetts, to Tahiti in 1938.

He was reportedly worried that his fellow Marines would not take him seriously because of his Hollywood fame, and so he adopted the pseudonym "John Hamilton", which he would carry throughout his war service.

[17][18][19] He received the Silver Star for gallantry in action in the Balkans and Mediterranean (according to his citation, "Lt. Hamilton displayed great courage in making hazardous sea voyages in enemy-infested waters and reconnaissance through enemy-held areas"), a Bronze Arrowhead device for parachuting behind enemy lines, and a commendation from Yugoslavia's Josip Broz Tito.

[20] He returned to the United States and told the press, "I feel a real obligation to make this a better country – and I believe the movies are the place to do it.

[22] Hayden made two films for Pine Thomas Productions which distributed through Paramount: one was a Western, El Paso (1949), featuring John Payne; the other was Manhandled (1949), a thriller with Dorothy Lamour.

In 1950, Hayden appeared in one of his most celebrated roles as the tough-guy gunman Dix Handley in the Academy Award-nominated film The Asphalt Jungle.

Immediately, a large group of movie luminaries, including Hayden, formed the Committee for the First Amendment to protest what they perceived as political harassment.

In the next few years, as the Second Red Scare gripped the U.S., the HUAC expanded its probe to include all entertainment industry professionals with suspected links, past or present, to the CPUSA.

[24] Gang first sent a letter to FBI Director J. Edgar Hoover, asking about "an unnamed client who had joined the Party as a youthful indiscretion, now regretted it, and wanted to clear his name."

Hoover recommended talking to the local FBI people, "so that if anybody subsequently makes a complaint we'll know he [the unnamed client] is all right as far as we're concerned.

[25] Gang then met with HUAC Chief Counsel Frank Tavenner to work out an acceptable format for Hayden's testimony.

[14] Due to his decorated war service in the Marines, and his decision to cooperate with the Committee, Hayden received favorable press coverage during this period.

[26] But Victor Navasky reminds us that the actor "named his former mistress, Bea Winters (his agent's secretary), who had recruited him into the Party.

He followed these two performances with a series of action films: Denver and Rio Grande (1952), a Western for Paramount; Hellgate (1952), another Western; The Golden Hawk (1952), a pirate swashbuckler for producer Sam Katzman; Flat Top (1952), a Korean War drama; and Fighter Attack (1953), a World War II film.

In November 1952, at the start of his lengthy divorce from his second wife, Betty Ann de Noon (whom he married in 1947[31]), it was revealed in court proceedings that he made $100,000 in the prior year.

[36] In 1959, he defied a court order, which barred him from taking the children out of the U.S., by sailing to Tahiti with all four: Christian, Dana, Gretchen and Matthew.

Marin County Superior Court Judge Harold Haley later ordered Hayden to repay Republic Pictures nearly $50,000 to recover the cost of financing the trip.

"[41] In the early 1960s, he rented one of the pilot houses of the retired ferryboat Berkeley, docked in Sausalito, California, where he lived while writing his autobiography Wanderer, which was first published in 1963.

[3] In 1963, Stanley Kubrick coaxed Hayden out of retirement to play one of his best-known characters, the deranged General Jack D. Ripper in Dr. Strangelove (1964).

[42] Hayden returned to acting with Hard Contract (1969), supporting James Coburn and Loving (1970), co-starring George Segal and Eva Marie Saint.

[44][45] In the 1970s, after his performance in The Godfather reintroduced him to American audiences, Hayden appeared several times on NBC's Tomorrow Show with Tom Snyder.

[7] Hayden received the following awards during World War II: Hayden, under his nom de guerre Lieutenant John Hamilton, and in his role as an OSS agent, appears as a secondary figure in the 2012 novel Death's Door: A Billy Boyle World War II mystery by author James R. Benn.