Schauffele had gone two years without winning and arrived in Kentucky having been left in Rory McIlroy's wake last week, but this time stood tall amid challenges from two world-class pursuers.
Hovland briefly held the lead on his own after Schauffele had opened the door with a bogey at the 10th, but the American birdied the next two holes to reassert his authority and was able to par his way to the 18th, where birdie was enough to win by one.
DeChambeau's fading hopes were reignited with an approach to three feet at the 16th hole and he got up and down for another at the last to move ahead of Hovland and alongside Schauffele, who was about to play his approach to the 17th from a fairway bunker.
Schauffele missed the green but was able to scramble par and went on to match DeChambeau's closing four to win a major championship for the first time, adding it to an Olympic gold medal.
Opening birdie sets the tone
Schauffele's day began in dream fashion with a birdie from almost 30 feet at the first, before tapping in for another at the fourth, getting up and down for birdie at the seventh, then holing from 10 feet for another at the ninth.
Ahead playing the par-five 10th, his decision to go for the green from a fairway bunker backfired as he eventually ran up a bogey six following a poor chip shot, but his response was an emphatic one as he fired an approach to eight feet at the difficult 11th.
Schauffele birdied the 12th from six feet after another fine iron shot and he was never again behind, making a string of two-putt pars from long distance until roars from the 18th confirmed DeChambeau had joined him on 20-under.
A delicate chip from the side of the 17th green was enough to secure the par which left him needing birdie to win at the par-five closing hole, the easiest on the course, but the task was made more complicated by an awkward lie following a pulled tee-shot.
Schauffele played a bold four-iron short and left of the green, leaving a clear pitch to the flag, a fine shot that made the next one easier. After hitting his third to six feet, he holed the putt to finally shake the monkey off his back.
“I was actually kind of emotional after the putt lipped in,” Schauffele said. “It’s been a while since I’ve won and I kept saying it all week, I just need to stay in my lane.
“Man, was it hard to stay in my lane today, but I tried all day to just keep focus on what I’m trying to do and keep every hole ahead of me. Had some weird kind of breaks coming into the house, but it’s all good now.”
He continued: “I really didn’t want to go into a play-off against Bryson. It would have been a lot of work. I just told myself, this is my opportunity, just capture it.
“I am very satisfied. I’m tired. Once I sat down in scoring, I felt a little bit more tired. But just a whirlwind of emotions.
“I knew I had to birdie the last hole, looking up at the board. It was a hectic birdie, as well, but it was awesome. I kept telling myself, I need to earn this, I need to prove this to myself and this is my time.”
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