In the gritty streets of Philadelphia, a small-time boxer named Rocky Balboa struggles with life as a loan shark enforcer. Despite his tough exterior, Rocky dreams of proving himself in the boxing world, but his ambitions seem far beyond reach as he faces the harsh realities of his existence. Living in a dilapidated apartment and training in a run-down gym, Rocky's life is a portrait of unfulfilled potential, underscored by his awkward attempts at wooing Adrian, a shy pet store clerk with her own set of insecurities. Their budding relationship, filled with vulnerability and mutual respect, becomes a beacon of hope in Rocky's otherwise bleak existence.

An unexpected opportunity presents itself when Apollo Creed, the reigning world heavyweight champion, in need of a gimmick for his upcoming title defense on New Year's Day, decides to give an unknown contender a shot at the title. Creed's search for an opponent with a "Cinderella" story leads him to Rocky, based on his nickname "The Italian Stallion" and his ethnic background, thinking it would make a good show for the bicentennial celebration. Seizing what he understands may be his one and only chance to rise above his station, Rocky dedicates himself to the fight, undergoing rigorous training with Mickey, a grizzled former boxer-turned-trainer who has his own history and demons. Together, they work towards molding Rocky into a contender, despite widespread skepticism from the public and even those closest to him.