Danny Lee and Justin Rose soared up the leaderboard to tie Stenson for second.
With the win, Spieth collected $1,485,000, making him the first player in PGA Tour history to eclipse the $12 million mark in earnings for one season.
Lee mixed seven birdies with two bogeys in his round.
Whilst Lee’s season was an undoubted breakthrough, Spieth capped off his own dream season when he closed with the 1-under 69 for a four-shot victory.
While it doesn’t count as “official” money, he will also bank the FedEx Cup bonus of $US10 million ($A14.23 million). Still, his two tour wins made him part of another notable feat: The tour had 24 wins by players in their 20s this year, the most since 1970.
The 22-year-old Spieth, who won the U.S. Open and Masters this year, also reclaimed the world number one ranking as Jason Day faltered.
The US Masters and US Open champion took a one-shot lead over Stenson into Sunday’s final round and had doubled his advantage by the turn, despite dropping shots on the fifth and sixth holes.
The day before the FedExCup, Jordan spoke to ESPN to tell them about his hopes for the event, which he would go on to win.
“I need to play those (first six) holes a lot better tomorrow”, he added.
Dustin Johnson shot a 6-under 64 – the low round of the day – to climb into a tie for fifth.
His battle with Henrik Stenson long over, Spieth finished it off in fitting fashion.
While Stenson’s week fell apart on the back nine on Sunday, it wasn’t all his fault – Stenson was left visibly frustrated after Spieth dropped bombs on top of him every time Stenson had an opportunity to get back into the tournament with a clutch birdie or par save.
At that point, Stenson could only smile and bump fists with Spieth.
So while several players can pat themselves on the back for successful seasons, it was all about Spieth at East Lake, and the crowds made that clear as he walked down the final stretch at 18.
“I got to work, put my head down a little more than I did right after the PGA, knowing that we could still peak this week and that’s what we did”.
He then tied for second at the PGA Championship, but missed the cut in the opening two FedEx Cup playoff events before bouncing back when it most mattered at East Lake.
During that period, he lost his grip on the world No. 1 ranking, first to Rory McIlroy, then to Jason Day.
The American’s putter was red hot, and with his Swedish partner stuttering, the Texan holed a 45 foot birdie putt on the 11th hole to take a stranglehold, before he parred his way in for the win.