While preparing for the film, De Niro joined LaMotta for one-to-one training sessions. Remembering his boxing lessons in a 2013 interview with Time magazine, the actor recalled: “I sparred with people with gear on, but we were careful. We weren’t looking to kill anyone. Then I trained with Jake. He would say, ‘Hit me, don’t worry, don’t worry.’ He was 55, but he was really tough. I didn’t realize until I got to his age that you could still take a punch.”
LaMotta was inducted into the Boxing Hall of Fame in 1980. After retiring from the sport, he invested in chain of bars, and began a part-time career as a stand-up comedian.