In 1944, at age 18, during World War II, Aldo entered the United States Navy, serving as a frogman until 1946; he saw action at Okinawa with UDT-17. Upon leaving the Navy in May 1946 he returned to Crockett. He studied and played football at Vallejo Junior College, then entered the University of California at Berkeley to study political science. (Ray later described himself as an "arch conservative" and a "right winger".) He left college in order to run for the office of Constable of the Crockett Judicial District in Contra Costa County California. "I always knew I was going to be a big man but I thought it was going to be in politics", he said.

Columbia refused to release him from his contract and put him under suspension, giving him a leave of absence to work as constable. "I told them I couldn't care less, they could give me whatever they wanted", he said. Ray started his new job in November 1950.

Harry Cohn felt the name "Aldo Da Re" was too close to "Dare" and wanted to change it to "John Harrison"; the actor refused and "Aldo Ray" was the compromise. He divorced his wife and resigned as constable in September 1951. His wage was $200 a week.

In 1953, he starred opposite Jane Wyman in Let's Do It Again, then followed this acting opposite Rita Hayworth in Miss Sadie Thompson (1953), a remake of the W. Somerset Maugham story "Rain". He also appeared in a production of Stalag 17 at La Jolla Playhouse.

Battle Cry was a big hit at the box office so Columbia gave Ray a lead role as a sergeant who marries a Japanese girl in Three Stripes in the Sun (originally The Gentle Wolfhound), then loaned him to Paramount for We're No Angels (1955), in which he starred with Humphrey Bogart, Peter Ustinov, Basil Rathbone, Leo G. Carroll, and Joan Bennett.

In 1956, in between appearances in Three Stripes In The Sun and Men in War, Ray tried his hand at radio, working as a personality and announcer at Syracuse, New York hit music station WNDR. A photo of Ray with a colleague in the WNDR studios, taken as part of a station promotional package, survives and can be found on a WNDR tribute website, although it's not known if any aircheck tapes of his radio shows still exist. By 1957, in any event, he had left WNDR and the radio Business and returned to Hollywood.

Columbia loaned out Ray to Security Pictures (who released through United Artists) to appear in Men in War (1957), opposite Robert Ryan; it was directed by Anthony Mann, who became Ray's favourite Director. Ray was given 5% of the profits which he later estimated at having earned him $70,000.

Ray had been popular with Harry Cohn because, in the actor's words, "He took no shit from anybody and he saw that I was that kind of a guy, too." But when Cohn died in 1958, Columbia elected not to renew Ray's contract and he decided to leave Hollywood. He later said "I never was an expatriate. I spent some time in England and Spain and Italy but I was never out of this country [the US] longer than six months."

In 1959, Ray was cast as Hunk Farber in the episode, "Payment in Full" of the NBC western series, Riverboat. In the story line, Farber betrays his friend and employer to collect reward money, which he uses to court his girlfriend, Missy.

As the 1960s ended, Hollywood's appetite for Ray's machismo started to wane. Though he worked steadily in the 1970s, the quality of his roles diminished, and he was typically cast as gruff and gravelly rednecks.

Ray returned to Hollywood in 1964. He had a small role in Sylvia (1965) and made a pilot for a TV series financed by Joe E. Levine, Steptoe and Son (an unsuccessful adaptation of the British TV series). "I feel I shall have a complete regeneration of my career", he said in 1965.

Ray starred in Kill a Dragon shot in Hong Kong in 1966, and Suicide Commando shot in Rome and Spain in 1968. He also made two television pilots in the 1960s; neither was picked up.

In 1976 he said he was broke. He blamed this on his ex-wives and red tape that meant he could not develop his real estate properties. "I lost it all", he said. "And I am very very bitter about it.... The biggest mistake I ever made was discovering women. I only wish society had been as free and easy when I was coming along as it is today because if that had been the case I wouldn't have been married. Three women in my life utterly destroyed me."

In 1979, Ray appeared in a pornographic movie, Sweet Savage, in a non-sexual role. Ray said later:

His career decline accelerated in the 1980s, and after being diagnosed with throat cancer, he accepted virtually any role that came his way to maintain his costly health insurance. He returned to Crockett in 1983.

In 1981 Ray told a newspaper that his drinking was "under control" and "I think things are going to shoot straight up. I'm working on a deal now and if the picture is made my worries... are over... If things go the way I anticipate and I stay healthy I think I've got better years ahead of me than behind me." He said he was open to a return to politics "if my movie career doesn't take off like I think it will." He admitted being unhappy with his career saying "I think I should have gotten more good stuff."

Ray was originally cast in the role of Gurney Halleck in David Lynch's 1984 adaptation of Frank Herbert's novel Dune, but was replaced by Patrick Stewart due to ongoing issues with alcoholism.

In 1986 Ray's SAG membership was revoked when it was discovered he was acting in a non-union production, Lethal Injection. However Ray still got his union pension and benefits. His fee at this stage was $5,000 a week.

His last film was Shock 'Em Dead which was filmed in 1990 appearing with Traci Lords and Troy Donahue. The same year he was interviewed and said:

Ray remained in Crockett, with his mother and family and friends. On 19 February 1991 he was admitted to the Veterans Administration Hospital in Martinez, 40 miles east of San Francisco. He died of complications from throat cancer and pneumonia on 27 March. He was cremated and buried in Crockett, with a majority of the residents coming out to pay their respects.

Quentin Tarantino says Aldo Ray would have been ideal casting for the character of Butch in Pulp Fiction (1994), and the look of Butch in the film (as played by Bruce Willis) was inspired by Ray.

Brad Pitt's character in writer-director Quentin Tarantino's 2009 war film Inglourious Basterds is a soldier named "Aldo Raine."