A former boxer from the streets of Queens, he became a scene stealer with his portrayals of mobsters, cops and working men with soul.Burt Young, a burly Queens-bred actor who leveraged a weary gravitas and bare-knuckled demeanor to build a prolific career as a Hollywood tough guy in films like “Chinatown,” “Once Upon a Time in America” and, most notably, “Rocky,” for which he was nominated for an Academy Award, died on Oct. 8 in Los Angeles. He was 83.His death was confirmed by his daughter, Anne Morea Steingieser.With his bulldog build and his doleful countenance, Mr. Young amassed more than 160 film and television credits. He often played a mob boss, a street-smart detective or a bedraggled working man.But even when he played a villain, he was no mere heavy. Despite his background as a Marine and a professional boxer, Mr. Young brought layers of complexity to his work. The acting teacher Lee Strasberg, who once coached him, called Mr. Young a “library of emotions.”With his no-nonsense approach, he found a kindred spirit in another Hollywood tough guy, the filmmaker Sam Peckinpah, who directed him in “The Killer Elite” (1975), starring James Caan, and “Convoy” (1978), starring Kris Kristofferson and Ali MacGraw.“Both were mavericks and outlaws, with a deep respect for art,” his daughter said in a phone interview. “They understood each other because of the intensity and honesty Peckinpah demanded. He had no tolerance for lack of authenticity.”Throughout the early 1970s, Mr. Young made memorable appearances on television shows like “M*A*S*H” and in movies like the mob comedy “The Gang That Couldn’t Shoot Straight” (1971) and “Cinderella Liberty” (1973), a drama about a sailor (James Caan) who falls in love with a prostitute (Marsha Mason).He also proved a scene stealer in a powerful, if brief, appearance in “Chinatown” (1974), Roman Polanski’s neo-noir masterpiece, as a cuckolded Los Angeles fisherman who becomes entangled in a tale of incest and murder.His true breakout came two years later, with “Rocky,” the story of a low-level hood and club boxer (Sylvester Stallone) who gets an unlikely bout with the heavyweight champion, Apollo Creed (Carl Weathers). Mr. Young played the combustible Paulie, a butcher friend of Rocky’s and the brother of Adrian (Talia Shire), the introverted woman who becomes Rocky’s girlfriend.Although “Rocky” would propel Mr. Stallone, who also wrote the screenplay, to stardom, Mr. Young often said that he had been the bigger name in Hollywood before the project began. “I was the only actor that didn’t audition in the first ‘Rocky,’” he said in a 2017 interview with The Rumpus, a culture website. “And I got the most money for it.”Mr. Young remembered his first meeting with Mr. Stallone, in a studio commissary. “He kneels down next to me,” he recalled. “He says, ‘Mr. Young, I’m Sylvester Stallone. I wrote Rocky,’” — and then, Mr. Young said, he added, “You’ve got to do it, please.”“He’s trying to twist my arm,” Mr. Young said.The film, a gritty and often somber human drama directed by John G. Avildsen, was a far cry from its sometimes cartoonish sequels, all but one of them directed by Mr. Stallone, in which Mr. Young also appeared. “It really wasn’t a fighting story, it was a love story, about someone standing up,” he said of the first movie in a 2006 interview with Bright Lights Film Journal. “Not even winning, just standing up.”“Rocky” became a 1970s landmark. It received 10 Academy Award nominations, including Mr. Young’s for best supporting actor, and won three Oscars, including for best picture.“I made him a rough guy with a sensitivity,” Mr. Young later said of Paulie. “He’s really a marshmallow, even though he yells a lot.”Mr. Young as Paulie in the original “Rocky.” The character was prone to volcanic eruptions, which including smashing up his sister’s house with a baseball bat.Everett CollectionBurt Young — he adopted that name as an actor; sources differ on his name at birth — was born on April 30, 1940, in Queens. His father was a sheet-metal worker, an iceman and eventually a high school shop teacher and dean.Growing up in a working-class neighborhood in the Corona section of Queens, Mr. Young got an early taste of the streets. “My dad, trying to make me a gentler kid, sent me to Bryant High School in Astoria, away from my Corona pals,” he wrote in the foreword to “Corona: The Early Years,” (2015), by Jason D. Antos and Constantine E. Theodosiou.“Soon, however, I got thrown out, and it was on to St. Ann’s Academy in Manhattan, getting booted out after one term,” he continued. “Finally, it was the Marines at 16, my pop fibbing my age to get me in.”He started boxing in the Marine Corps and went on to a successful, if relatively brief, professional career under Cus D’Amato, the boxing trainer and manager who shepherded the careers of Floyd Patterson and Mike Tyson. He had a win-loss record of about 17-1 — his own accounts varied — when he quit the ring.In his late 20s, he was laying carpets and doing other odd jobs when he became infatuated with a woman who tended bar, and who told him that she dreamed of studying acting with Mr. Strasberg. “I didn’t know who Lee Strasberg was,” he told Bright Lights. “I thought it was a girl.”Mr. Young set up a meeting for the two of them with Mr. Strasberg, the father of method acting, and ended up studying with him for two years. “Acting had everything I was fishing for,” he recalled. “In my life till then, I’d used tension to hold myself upright. Lee’s great gift to me was relaxation.”His many other film credits ranged from “Last Exit to Brooklyn” (1989), a harrowing adaptation of the scandalous 1964 novel by Hubert Selby Jr. about lost souls from the underside of midcentury Brooklyn, to the 1986 Rodney Dangerfield comedy “Back to School.” Mr. Young also wrote and starred in “Uncle Joe Shannon” (1978), the story of a jazz trumpeter whose life implodes before he finds redemption.In addition to his daughter, Mr. Young is survived by a brother, Robert, and a grandson. His wife, Gloria, died in 1974.Mr. Young, second from left, performed onstage with Robert De Niro, center, and Ralph Macchio, third from right, in “Cuba and His Teddy Bear,” which opened at the Public Theater in Manhattan in 1986.Ron Galella Collection, via Getty ImagesMr. Young also had a long career in theater, including a role alongside Robert De Niro and Ralph Macchio in “Cuba and His Teddy Bear,” a play about a drug dealer and his son that opened at the Off Broadway Public Theater in Manhattan in 1986 and later moved to Broadway.Mel Gussow of The New York Times praised Mr. Young’s humor-laced performance as Mr. De Niro’s partner and lackey. He singled out one scene for praise in which Mr. Young, he wrote, was “sheepishly pulling up the wide waistband of his loud shorts while insisting that he is not fat but has ‘big bones.’”Mr. Young was an avid painter who sold his work, and whose moody portraits showed the influence of Picasso and Matisse. “I don’t think you can put me in a bottle as an actor or an artist,” he said in a 2016 video interview. “Perhaps the acting, I’m a little more structured.”In acting, he added, he zeroed in on precise emotional cues to express, say, greed or anger — to “fatten up” his characters.Little wonder, then, that his Paulie in “Rocky” leaped off the screen with volcanic eruptions — tossing his sister’s Thanksgiving turkey into an alley in a fit of rage, smashing up her house with a baseball bat.“Paulie was a pretty ugly guy many times,” he said. But, he added, “they miscast me.“I’m a lovable son of a gun. It’s just that I go astray here and there.” More