Daniel Eugene "Rudy" Ruettiger, portrayed by Sean Astin, grows up in Joliet, Illinois with a deep-seated dream of playing college football at the prestigious University of Notre Dame. Despite finding some success on his high school team, Joliet Catholic, Rudy faces significant obstacles, including poor grades, financial constraints, and a lack of the physical prowess typically required for a major intercollegiate football program.
After taking up work at a local steel mill, where his father, Daniel Sr., also toils and nurtures a love for Notre Dame, Rudy's plans seem to shift toward a life of stability. However, a tragic incident involving the death of his best friend Pete in a mill explosion sparks a renewed commitment in Rudy to pursue his ambitions. Fueled by grief and determination, he sets his sights on attending Notre Dame and joining the Fighting Irish.
Rudy makes his way to South Bend, Indiana, with aspirations of enrollment, but his applications are unsuccessful. With support from a local priest, he manages to gain admission to Holy Cross College, a junior college nearby, with hopes of transferring to Notre Dame after boosting his grades. In an effort to immerse himself in the world of Notre Dame football, Rudy volunteers to assist Fortune, the stadium groundskeeper, even going so far as to sneak into the office at night to sleep on a cot, as he is without a home.
Though initially indifferent, Fortune begins to admire Rudy's perseverance and eventually makes him feel welcome by granting him a key to the office. Rudy learns a shocking revelation about himself when he befriends D-Bob, a graduate student who offers tutoring in exchange for help in dating. D-Bob discovers that Rudy has dyslexia, but with new strategies, Rudy begins to excel academically.
As Christmas approaches, Rudy revisits his family, who begrudgingly acknowledge his improvements, but he faces mockery for his football ambitions and even loses his fiancée to a brother. Despite multiple setbacks, Rudy is thrilled when he is finally accepted to Notre Dame during his final semester eligible for transfer. The joyous news is shared with his family, and they announce it to his father's co-workers over the mill's loudspeaker.
Once at Notre Dame, Rudy works hard and earns the chance to practice with the football team, despite being a non-scholarship player. Coach Ara Parseghian acknowledges Rudy's extraordinary drive, which does not go unnoticed by the scholarship players, who begin to resent him for outshining them. Rudy pushes through the challenges, gaining the right to suit up for one home game in his senior year under the coach's encouragement.
However, with Coach Parseghian's departure after the 1974 season, new coach Dan Devine refuses to include Rudy on the active roster. Disheartened, Rudy quits the team upon realizing he won’t play in the upcoming game. A pivotal moment arises when Fortune, now a pivotal mentor, intervenes, reminding Rudy that the only person he needs to prove anything to is himself. This conversation reignites Rudy's spirit, prompting him to return to the team.
In a display of camaraderie, team captain Roland Steele and his fellow seniors protest for Rudy to be allowed to dress for the final game against Georgia Tech, even offering their jerseys. In response, Coach Devine permits Rudy to suit up.
As the game unfolds with Notre Dame leading 27-3, the moment of truth arises. Despite a last-minute push from his teammates, Rudy is not initially called to play. However, as cheers for "Rudy!" erupt from the crowd, the team overrides Devine's strategy, providing Rudy with the chance he long desired. In a heartwarming climax, Rudy steps onto the field for the final play, manages to sack the Georgia Tech quarterback, and is celebrated as he is hoisted onto his teammates' shoulders, a triumphant symbol of perseverance and determination in the face of adversity.
