Roy Hobbs is a young pitching prodigy from Nowheresville. The novel opens on a train, where Roy and his friend/scout, Sam, are headed to Chicago so Roy can try out for the Cubs. They meet the Whammer, the reigning American League MVP, and a sportswriter named Max Mercy, but these two don't give Sam and Roy the time of day. In fact, the Whammer even picks up a girl that Roy had his eye on, a pretty lady named Harriet.
The train makes an unexpected stop and Sam proposes a friendly wager: he bets that Roy can strike out the Whammer. Good news: Roy does. Bad news: the last pitch hits Sam hard in the chest (he's playing catcher) and knocks the wind out of him. Now that Roy's defeated the Whammer, he's got Harriet's attention.
That night Sam dies, leaving Roy to try to manage on his own. At the hotel in Chicago Harriet somehow gets Roy's number and invites him to her room in the same hotel. She shoots him. It turns out she's a psycho that's been murdering great athletes.
The novel picks up many years later in New York where Roy, now thirty-three, has a contract with the Knights, the last place team in the league. Knights general manager Pop Fisher thinks that the club owner, the Judge, is trying to blow their chances by saddling them with an aging player. Pop's dream has been to win the league pennant, but it's not looking good for the Knights.
Knights star player Bump Baily is a big jerk who loves to play practical jokes and won't make an effort on the field. He and Roy quickly become rivals, not least because Roy digs Bump's girlfriend, Memo Paris, aka Pop Fisher's niece. Trying to outdo Roy in the hustle department, Bump runs into the outfield wall chasing a fly ball and ends up dying from his injuries.
Roy's been lighting up the Knights with his fielding and batting. Sportswriter Max Mercy is back in the picture. He feels he's met Roy before and wants to dig up dirt on this mysterious guy's past. He invites Roy out for drinks and they run into Memo and a bookie named Gus. Gus offers to make Roy rich if he'll cooperate with him in fixing some games. Roy's insulted and refuses; he doesn't get why Memo would hang around with a guy like that.
Roy keeps hitting and the Knights keep winning. The team honors Roy with a "Roy Hobbs Day," and he gets tons of presents and prizes from local stores, including a Mercedes-Benz. He takes Memo out for a spin.
Pop warns Roy that his niece is bad news. Sure enough, Roy gets into a batting slump right after their night out. The slump continues until one day he sees a woman standing up in the stands during his at-bat. Roy knocks a pitch out of the park. Roy finds the mystery woman and they go out on a date. She turns out to be sympathetic and supportive of Roy's dreams. They're making love when she tells him that she's a grandmother at age 34, which Roy just can't handle.
So Roy goes back to the young and beautiful Memo, who invites him to a party to celebrate the team's success—they're one playoff game away from the World Series. Roy eats everything in sight and gets sick (it turns out Gus paid for the party—maybe the food was poisoned) and ends up in the hospital.
While he's recuperating, he asks Memo to marry him; she says she can't because he's poor. Then she offers him money to throw the game. The Judge shows up and offers him even more, and Roy finally accepts. He thinks this is his big chance to get Memo.
Roy deliberately fails to hit in the big game. But he starts to regret it and takes a wild hit. The ball smacks Iris in the stands, and before she's carted off to the hospital she tells Roy he has to win for their kid; she's pregnant.
As usual in these kinds of stories, the game comes down to Roy's last at-bat. But there's no joy in Mudville; our hero strikes out and Pop's pennant hopes go down the drain. Max Mercy publishes an article accusing Roy of throwing the game, and Roy's career ends in disgrace for Roy and disappointment for his fans. Roy's left to wonder why he never learned anything from all his mistakes.