Dustin Johnson only looks like he plays without a pulse. Beneath his stoic stare and that swagger as he walked the fairways of East Lake on Monday were jangled nerves because it meant so much to him.

The $15 million prize for winning the FedEx Cup? That would get anyone’s attention, especially someone who thought he was rich when Johnson cashed his first tournament check for $113,571 as a PGA Tour rookie.

“The prestige, for sure,” Johnson said after delivering a key par putt and steady play down the stretch for a 2-under 68 and a 3-shot victory in the Tour Championship.

“Being a FedEx Cup champion is something that I really wanted to do. I wanted to hold that trophy at the end of the day. It was something that I wanted to accomplish during my career.”

He won two of the three FedEx Cup postseason events and lost in a playoff by a 65-foot putt in the other. It all came down to the final day of the final event, and even with a 5-shot lead, it was never easy.

Xander Schauffele and Justin Thomas each got within 3 shots on the front nine. They each got within 2 shots of Johnson with two holes to play. Johnson never let them catch him, and his only birdie of the back nine on the final hole gave him his third victory since June and the 23rd of his PGA Tour career.

“It’s a very tough trophy to win,” Johnson said. “I controlled my own destiny, but I still had to go out and play well. I had a lot of great players right behind me. It got close at the end. I knew it was going to come down the stretch and I’d have to hit some golf shots.”

Johnson became the first No. 1 seed at the Tour Championship to win the FedEx Cup since Tiger Woods in 2009. Now Johnson has his name etched on the silver trophy alongside some of the best from his generation, starting with Woods and most recently Rory McIlroy, with Hall of Famers, major champions and former world No. 1 players in between.