In the year 1941, Jake LaMotta, a promising young middleweight boxer, faces his first defeat against Jimmy Reeves due to a questionable ruling. His brother, Joey, seeks to secure a title shot through connections with the Mafia's Salvy Batts, but determined to rise through sheer skill, Jake consistently rejects their assistance. Shortly after, he encounters a young girl named Vickie at a swimming pool in the Bronx, ultimately leading to a complicated relationship, despite Jake already being married and Vickie being underage. By 1943, Jake manages to beat the renowned Sugar Ray Robinson, only to face a controversial rematch three weeks later where he dominates the match, yet the judges, much to Joey's dismay, award the victory to Robinson—an outcome Joey suspects is influenced by Robinson's upcoming Army enlistment. By 1945, Jake marries Vickie.
Once married, Jake's controlling nature surfaces. His jealousy over Vickie’s supposed feelings for other men grows as he shows this side by savagely defeating opponent Tony Janiro in front of Tommy Como, the local mob boss, and Vickie. In a moment filled with tension, Joey notices Vickie mingling with Salvy and his crew. After a conversation reveals her discontent in her marriage, Joey jumps to the conclusion that she is, in fact, having an affair with Salvy, leading to a brutal fight between the two. Forced to apologize by Como, Joey informs Jake that a title shot depends on him taking a dive. Reluctantly, Jake loses a rigged match against Billy Fox, earning the crowd’s scorn for his subpar performance. Although he faces suspension under the suspicion of match-fixing, his resolve helps him regain his footing, leading to a triumphant win against Marcel Cerdan for the middleweight championship title in 1949.
As time passes, paranoia creeps in, and by 1950, Jake suspects Vickie of infidelity. Tension escalates when he confronts Joey with accusations, causing a rift that drives him away. Later, as Jake pressures Vickie, she sarcastically suggests that she has been unfaithful—not only with Joey but also with others such as Salvy and Tommy. Consumed by rage, Jake storms to Joey's home, unleashing violence in front of Joey’s family and accidentally knocking Vickie out. Eventually, they find their way back to each other. After an intense fifteen-round defense of his championship against Laurent Dauthuille, he tries to reconcile with Joey, but a misunderstanding causes him to sever ties further, leading to a tragic decline in his career and a title loss to Sugar Ray Robinson in 1951.
By 1956, the once-proud Jake has aged and gained weight, retiring to Miami with his family. His reckless nights out lead Vickie to demand a divorce and threaten to keep their children away from him, highlighting the fallout of his failures. Facing legal troubles for introducing underage girls to his nightclub, he futilely attempts to use his championship belt's jewels for bribery, leading to incarceration in 1957 where he grapples with despair over his situation. Upon returning to New York City in 1958, a reunion with Joey results in a tentative embrace, hinting at the repair of their fractured relationship.
Fast forward to 1964, Jake embarks on a new venture in stand-up comedy, where he prepares for performances by shadowboxing and recalling memorable lines from On the Waterfront, exclaiming, > "I'm the boss," before stepping into the spotlight, symbolizing his relentless pursuit of redemption and acknowledgment.
