The 28-year-old finished a shot ahead of Anirban Lahiri at TPC Sawgrass, going home with the winner’s check of $3.6 million.
Smith carded a six-under 66 to finish 13-under for the tournament and claim his second title of the season and fifth of his career.
When asked what he was going to do with such a large amount of money in the press conference afterwards, Smith hadn’t yet made up his mind.
“I really don’t — I don’t have an answer for that. It hasn’t sunk in,” he said with a smile.
“That’s a lot of money. I’m not sure what I’m going to do with it.”
And after a quick turnaround, Smith began his final round strongly with a huge 38-foot birdie putt on the first hole.
He registered five birdies in his opening six holes, before three consecutive bogeys from the seventh hole weakened his grip on the lead.
But, under huge pressure, Smith reestablished his lead with four straight birdies to start the back nine, giving him a three-shot lead heading into the final hole.
Lahiri birdied the 17th behind Smith to cut the lead to two, while on the 18th, Smith hit his ball into the water as it looked like the title might be slipping away.
However, he managed to salvage bogey, leaving Lahiri needing a birdie to force a playoff, but the Indian golfer could only manage a par, cementing Smith’s victory.
The victory meant he became the fifth Australian to win the famous event, moving Smith up to sixth in golf’s world rankings.