James J. Braddock, portrayed by Russell Crowe, is a determined Irish-American boxer hailing from New Jersey. Once considered a light heavyweight contender, he finds himself compelled to abandon the ring after suffering a severe hand injury. This situation brings a mix of relief and concern for his wife, Renée Zellweger. Mae, his supportive spouse, is deeply pained by the brutality of his profession, yet she realizes that their financial situation heavily relies on his boxing career.

As the Great Depression wreaks havoc across the nation, Braddock takes on physically demanding work as a longshoreman, struggling to provide for his family despite his injured hand. Daily work is far from guaranteed. However, fate intervenes when Braddock’s loyal manager and friend, Joe Gould, offers him a last-minute opportunity to fight due to a cancellation by another boxer. This fight pits him against the formidable Corn Griffin, the number-two contender in the world.

Against all expectations, Braddock astonishes both experts and fans alike with a remarkable third-round knockout victory over Griffin. He comes to realize that while his right hand may be broken, his left hand has effectively improved, enhancing his skills in the ring. Ignoring Mae’s concerns, Braddock decides to seize the opportunity to return to boxing. Initially, Mae is skeptical of Gould’s intentions, viewing it as an exploitative effort to capitalize on Braddock’s perilous career. However, her perspective shifts when she learns that Gould and his wife also face significant hardships.

As Braddock continues on his winning streak, a shot at the heavyweight championship held by Max Baer becomes a tantalizing possibility. Demonstrating immense pride, Braddock dedicates a portion of his earnings to repay the government for unemployment assistance they had received during difficult times. His remarkable rise from adversity captures the public’s imagination, leading sportswriter Damon Runyon to label him “The Cinderella Man,” symbolizing the aspirations of countless Americans grappling with the Depression.

An impending title fight against Baer places Braddock in the role of a 10-to-1 underdog. Mae is understandably fearful of facing the cruel champion, who has a notorious reputation for causing serious injury in the ring, including the deaths of at least two opponents. To prepare them for the daunting challenge, the promoter, James Johnston, insists that both Braddock and Gould watch a film of Baer in action, highlighting the dangers that lie ahead.

Despite the intimidation tactics employed by the arrogant Baer, who even goes so far as to provoke Mae by suggesting her husband might not survive the upcoming fight, Braddock remains unfazed. Mae’s distress escalates to the point where she cannot bear to attend the fight at Madison Square Garden or listen to its radio broadcast.

On June 13, 1935, in a defining moment for boxing history, Braddock triumphs over the seemingly unbeatable Baer, claiming the title of heavyweight champion of the world. The film concludes by revealing that Braddock later contributed to the construction of the Verrazano Bridge and operated heavy machinery at the docks, where he had once worked during the hardships of the Depression. Ultimately, he and Mae used their winnings to purchase a home, enjoying a life together filled with lasting memories.