McIlroy surged past Brooks Koepka to win the FedEx Cup and its $15 million prize, at East Lake in Atlanta.
One shot behind, McIlroy took the lead with a three-shot swing on No. 7 and never let Koepka or Xander Schauffele catch him.
McIlroy closed with a 4-under 66, a score that would have won the Tour Championship in any scoring format. He finished four shots ahead of Schauffele.
“I’m going to enjoy this one tonight,” he said.
McIlroy had more than the $15 million prize on his mind.
He wanted to win this outright and was keeping score until the very end. The format was changed this year to give top players a head start based on par depending on their standing in the FedEx Cup. Justin Thomas was the No. 1 seed and started at 10-under par before a shot was hit. McIlroy was the No. 5 seed and started at 5 under.
He finished at 18 under in the FedEx Cup finale. His actual score was 13-under 267, better than anyone else in the 30-man field.
His win boosts him to No. 2 in the world behind Koepka.
He joined Tiger Woods as the only players to win the FedEx Cup twice since it began in 2007.
A year ago, he was merely a bystander playing in the final group as Woods capped off his comeback by winning at East Lake.
“It’s amazing how different things can be in a year,” McIlroy said.
The Associated Press contributed to this report.