Dufner, who is not prone to displays of emotion, allowed himself a sheepish smile and a hesitant double fist bump following a two-shot victory over Jim Furyk.
But he left the real celebrations to the galleries packed around Oak Hill Country Club's 18th green that watched him clinch the season's final major two days after he shot a 63, matching the lowest round in any major.
Until Dufner planted a shy kiss on the shiny Wanamaker trophy in the fading sunlight, he was best known as a social media sensation - the inspiration behind the 'Dufnering' craze which went viral.
Despite being a two-time winner on the PGA Tour, it was not until last April when golf fans began to take notice of Dufner when he was photographed apparently nodding off as he lay with his back to a wall, arms by his sides and legs stretched out in front of him while visiting grade schoolers to help promote a tournament in Dallas.
Since then, multiple versions of 'Dufnering' have been posted by golfers, golf fans and the general public on social media.
"Got some notoriety for maybe something that was probably trying to hurt me a little bit and ran with it and it helped me a lot," said Dufner. "I got a lot of fans because of it and people identified me through it and that was good."
Until 'Dufnering', the only notoriety Dufner had was for spectacularly blowing a five-shot lead with four holes to play at the 2011 PGA Championship and eventually losing to Keegan Bradley in a playoff.
There would be no repeat of the Atlanta Athletic Club meltdown on a sunny, Sunday at Oak Hill.
Playing with cool consistency, Dufner seized the outright lead from Furyk with a birdie on the fifth hole and never faltered, opening up a two-shot cushion at the ninth and holding it through to the finish.
Furyk, bidding to add a PGA Championship to the U.S. Open title he won a decade earlier, was unable to put any pressure on the unflappable Dufner, who went 26 consecutive holes without a bogey before dropping a shot at the 17th.
But Furyk also dropped a shot on the penultimate hole to remain two behind.
It was a remarkable display of composure for a man that must surely have lived with the haunting memories, of two years ago when the Wanamaker trophy was within his grasp, only to let slip through his fingers.
"You always carry those scars with you, he (Bradley) always jabbed at me a little bit about having one of these in his house, and thanks for giving it to him and all that stuff," said Dufner. "And now I've got one, too.
"It's pretty neat to come back and win a PGA to be honest with you.
"My name will always be on this trophy and nobody can take that away from me, so it's a great accomplishment for me and I'm really excited about it."
Whether hitting a tee shot into the water, or carding a hole-in-one, Dufner's demeanor rarely changes.
The biggest victory of Dufner's career did not send him flying into the air like Phil Mickelson after his first Masters win or a violent fist-pump and scream like Tiger Woods.
While there was no hiding Dufner's delight at becoming a major winner, he explained his low-key approach is simply because there is not that much to get excited about.
"Big plays in basketball, home runs in baseball, big plays in football; those will get you pumped up," explained Dufner. "For me, golf is a little bit more boring I think.
"It's pretty matter of fact. I hit it in the fairway or I didn't; I hit the green or I didn't.
"Usually I'm struggling with the putter, so there's not too much to get excited about with that. I made that putt on the first hole, I would say I was pretty flat-lined for most of the day.
"I come across as a pretty cool customer I guess, but there are definitely some nerves out there, especially when you're trying to win a major championship."