His death was confirmed by his daughter, Anne Morea Steingieser, per the New York Times.

He made his big-screen debut in the 1970 horror film “Carnival of Blood” and then went on to appear in numerous films including the 1971 mob comedy “The Gang That Couldn’t Shoot Straight” and Roman Polanski’s 1974 neo-noir film classic, “Chinatown.” Young often played a working-class Italian American and had a penchant for bringing depth to tough-guy roles. Filmmaker Sam Peckinpah directed him in the 1975 film “The Killer Elite,” starring James Caan, and the 1978 action comedy “Convoy,” starring Kris Kristofferson and Ali MacGraw.

Both Young and Peckinpah “were mavericks and outlaws, with a deep respect for art,” his daughter said, per the New York Times. “They understood each other because of the intensity and honesty Peckinpah demanded. He had no tolerance for lack of authenticity.”

In 1976, Young shot to stardom portraying Paulie Pennino, the butcher buddy of Sylvester Stallone’s character in “Rocky.” He was nominated for an Academy Award for best supporting actor, which Stallone said Young should have won. “Rocky” received 10 Academy Award nominations and won three Oscars, including best picture.

Young also made television appearances in “M*A*S*H” and “The Equalizer” and performed on stage, including a role alongside Robert De Niro and Ralph Macchio in “Cuba and His Teddy Bear.” The theatrical production about a drug pusher and his son opened in 1986 at the off-Broadway Public Theater in Manhattan, then moved to Broadway.

Born in the Corona neighborhood of Queens, N.Y., on April 30, 1940, Young said he had “the greatest parents.” His father, Michael DeLouise, was a sheet metal mechanic who, Young said, became like a minister in the high school as a shop teacher and dean. “He could do anything, build anything. He was a tough guy himself,” Young said during an interview with visual production company Platinum Platypus. “My mother, Josephine — most beautiful lady ever — she protected me from everything. Mama knew I couldn’t do wrong.”

Growing up, Young was a natural boxer. “I was half a hoodlum,” he said. He joined the Marine Corps, where he boxed and — by his own count — won 32 of his 34 matches, he told The Times in 1985. He fought 14 professional fights and said he came out the winner in all.

Sylvester Stallone, left, mugs with “Rocky” co-star Burt Young before a 20th anniversary screening of the film on Nov. 15, 1996, in Beverly Hills.

(Chris Pizzello / Associated Press)

“Fighting, it was part of my nature,” he said. “And I did an exhibition with Muhammad Ali. That was one of my high spots, at the Olympic Auditorium in California; we became fast friends.”

Young had a carpet-laying business, and he had his love of boxing. But he said he felt unfulfilled.

It took meeting Norma, a young beauty in a gin mill in the Queens neighborhood of Jackson Heights, to steer him toward acting. He asked Norma if she’d ever considered becoming an actress and, according to Young, she lit up and said she hoped to study with the famed acting coach Lee Strasberg, who mentored Marilyn Monroe.

“I didn’t know who the hell was Lee Strasberg,” he said. But because of the young woman, he looked into Strasberg and wrote him a letter. If an acting background was a prerequisite “read no further,” he wrote. “If you’re still with me: Acting none, life credits plenty. … I don’t know if acting has anything for me or vice versa. But I’m treading water, see me.” According to Young, Strasberg took to the letter and invited him to his house in New York’s Central Park West.

Strasberg later said that Young was a “library of emotions.”

In 2014, the veteran actor was honored with a lifetime achievement award at the Hoboken International Film Festival. Stallone honored his former “Rocky” costar, saying, “I was very lucky to meet Burt Young in 1975, because this man is an anomaly. Incredibly strong, brave, worldly, intelligent, artistic and insightful. I guess that would certify him as a renaissance man.

“He brought such passion to the character of Paulie. I thought he should have won an Oscar; he was amazing,” he continued. “He would pull me aside and make suggestions. And he was very intuitive about dialogue and how to make the scene better. And he just brought an originality and a pacing, a verbalization, the way he phrased sentences, that caused me to go home and rewrite everything. I just wanted to be the guy lucky enough to capture the essence of Burt Young on film, and I believe we did that for many, many years. So Burt, I love you. I love your work, your writing, your painting, and most of all, luckily, I never got punched by ya, because he’s a knockout artist too. And a knockout as a human being.”

In addition to his daughter, Young is survived by a brother, Robert, and a grandson. His wife, Gloria, died in 1974.