The win ended a seven-year drought for the 34-year-old Na, who won the Shriners Open in Las Vegas in 2011 and despite some close calls had not taken home a trophy since.
But he returned to form Sunday to earn another top finish.
Bubba Watson shot 65 and was among three players at 11 under.
"My putter got hot", Na said.
Beginning the day a shot off the pace, Na birdied the fourth and added another at the par-four next before nailing a 30-footer at the sixth for a third straight gain.
"This feels awesome - I mean, I see the record (of time between wins) every time I'm on TV", Na said. Stallings finished his day tied for 13th at 9 under; Kevin Na is in 1st at 19 under; Kelly Kraft is in 2nd at 14 under; and Brandt Snedeker and Jason Kokrak are tied for 3rd at 13 under.
World's ugliest dog Zsa Zsa dies just weeks after winning title
Owner Megan Brainard of Anoka, Minnesota, told NBC's "Today " that Zsa Zsa died in her sleep Tuesday. Much like when she won the competition, the family is surprised by the news of her death.
Kraft received a good consolation prize in addition to the hefty second place cheque when he became one of the four players to earn at start at Carnoustie in ten days time being one of the four players not otherwise exempt to the Open Championship and finishing inside the top ten this week. His second PGA Tour win appears imminent. After stepping on the grass, he paused before he hit his tee shot, realized the mistake and checked with a rules official, who confirmed the violation. Bradley's putt lipped out and still rolled 7 feet past the hole, leading to a double-bogey. He improved 40 spots to No. 18 in the FedEx Cup standings.
Harold Varner looks at a putt on the first hole during the third roundKelly Kraft (right) gives his caddie a fist bump after a chip in birdie on the 11th hole.
After Knox made birdie on No. 18 to set the clubhouse target at 14-under par, Ryan Fox of New Zealand missed an 8-foot birdie putt that would have won him the Rolex Series event. Fox failed to match the birdie, with his putt agonizingly lipping out, and Knox put his hands to his face.
"It feels wonderful", Na said.
Phil Mickelson, in his first tournament since his freaky US Open final day meltdown on the 13th green, was penalised two shots on Sunday for improving his line of play. He started the final round just a shot behind the lead, but got things in gear with six birdies in a seven hole stretch from 4-10 on Sunday.