Happy Gilmore, portrayed by Adam Sandler, is a determined young man with aspirations of becoming an ice hockey player. Gifted with a powerful slap-shot learned from his late father, Happy struggles with a glaring lack of skating skills and a notorious aggressive demeanor, which continually hinders his efforts to secure a place on a hockey team. His situation worsens when he discovers that his beloved grandmother (Frances Bay), who raised him after his father's passing, has fallen behind on her tax payments, leading to a $270,000 debt to the IRS. With just three months to gather the funds, Happy faces the grim reality that their family home, built by his grandfather "with his bare hands," is set to be seized. Amidst this chaos, his grandmother is forced to move into a retirement home overseen by the sadistic manager Hal (Ben Stiller in an uncredited role).
While dealing with the moving of Grandma's belongings, a couple of movers challenge Happy to hit golf balls. To everyone's surprise, he sends them soaring over 400 yards with his unconventional slap-shot, earning $40 in the process. This unexpected success sparks an idea — Happy decides to visit the driving range where he can use his hockey swing to outsmart other golfers. Once his talent is noticed by Chubbs Peterson (Carl Weathers), a former golf champion whose career ended catastrophically after losing his right hand to an alligator, he encourages Happy to enter a local tournament where he could earn the money needed to save his grandmother's home.
Happy’s victory in the tournament earns him a spot on the Pro Golf Tour, but he disregards Chubbs' advice to wait six months to further refine his golfing skills. Instead, he jumps into the competition right away, quickly making an enemy of the pompous star, Shooter McGavin (Christopher McDonald), who perceives Happy as an unwelcome distraction and a threat to his own golf career. As Happy discovers the golfing world, he realizes that while his driving skills are impressive, his putting is lacking, and his wild behavior begins to attract Shooter's ire.
The tour's popularity surges due to Happy's antics, forcing Shooter to get creative in his attempts to have Happy expelled from the tour, leading him to hire a mentally unstable fan named Donald (Joe Flaherty) to taunt Happy during matches. At one event, Happy is paired with the iconic Bob Barker, known for his role as the long-time host of "The Price Is Right," leading to a chaotic situation fueled by Donald's provocations and culminates in a hilarious physical altercation with Barker, which results in Happy facing a hefty fine and suspension from the tour.
Despite the challenges, Happy manages to secure an endorsement deal with Subway, affording him enough funds to reclaim Grandma's house, only to find out when he arrives that it will be auctioned off. Shooter, seeing an opportunity, outbids him, intending to leverage control over Happy by making him quit the tournament in exchange for the house. However, Virginia Venit (Julie Bowen), the tour's PR head, intervenes, encouraging Happy to chase his dreams rather than settle for the house.
Determined to win back the house, Happy proposes a wager — if he finishes the Tour Championship above Shooter, he gets the house back; if not, he will leave the tour permanently. After some self-reflection and help from Chubbs, Happy hones his skills, particularly his putting, and they form an emotional bond, especially after Happy presents Chubbs with the head of the alligator that took his hand, only for the shock to result in a tragic accident.
As the tournament progresses, Happy and Shooter are neck and neck. In a last-ditch effort, Shooter employs Donald again, leading to a wild scene where Donald rams Happy with a Volkswagen Beetle. Undeterred and inspired, Happy overcomes the odds, applying the wisdom imparted by Chubbs and drawing encouragement from his grandmother.
The climax occurs on the 18th hole when both competitors face off, with Happy managing to tie Shooter against all odds, just before a freak accident collapses a TV tower, obstructing his path. In a moment of brilliance, using techniques he learned, he executes a miraculous trick shot to win the Tour Championship and, thus, regain his grandmother's home.
In the aftermath, Shooter's attempt to steal Happy's trophy jacket is thwarted by an unlikely hero in Happy's former boss, Mr. Larson (Richard Kiel), inciting a raucous crowd. The movie concludes with Happy enjoying heartfelt congratulations from the ghost of Chubbs, the spirit of Abraham Lincoln, and the fearsome alligator, encapsulating the film's blend of humor and heartfelt moments.
