Woodland punctuated the victory with a birdie bomb at 18, a final flourish in a display of back-nine fortitude that saw him convert a 54-hole lead for the first time in eight career attempts.
“Once that went in, it all kind of came out of me, it was special to finish it off here at Pebble Beach,” said Woodland, who threw his arms in the air then pumped his fist.
He knew his 13-under total was one better than the 12-under posted by Tiger Woods in his US Open victory at Pebble in 2000.
But 19 years ago, Woods was the only player under par, marching to victory by a massive 15 strokes while Woodland topped a leaderboard that featured 31 players under par.
Most dangerous was Koepka, trying to become just the second player – and the first in more than a century – to win the US Open three straight times.
He started the day four strokes off Woodland’s lead and immediately applied pressure with four birdies in his first five holes.
But his three-under 68 left him three strokes shy on 10-under 274.
Koepka did grab a slice of US Open history, becoming the fourth player to complete four rounds in the 60s. Minutes later, Woodland became the fifth with a final scoreline of 68-65-69-69.
“I was proud of myself to stay in my moment and control myself and not get too worried about what he was doing,” Woodland said.
England’s Justin Rose, who started the day one shot behind Woodland, struggled to a three-over 74 to finish tied for third on seven-under with Americans Xander Schauffele and Chez Reavie and Spain’s Jon Rahm.
Woodland, 35, took a two-shot lead with a bold birdie at the par-five 14th, where he powered his second shot to the short rough behind the green and chipped to three feet.
“The idea was to play to win,” Woodland said. “That birdie kind of separated me a little bit.”
He was in trouble at the par-three 17th, where his tee shot found the front right of the putting surface – on the wrong side of a ridge in the hourglass green.
Woodland opted to pitch up and the shot tracked straight toward the hole, settling two feet away.
“I was just trying to get it over that hump,” Woodland said. “Fortunately I had the same shot earlier in the week, so I already executed it once. It came off beautifully, and I thought it had a chance to go in there – it gave me a little cushion on the last.”
Woodland, who admitted he once had trouble handling the rush of adrenaline in pressure situations, displayed impressive poise on a day when plenty of players were pressing on a receptive Pebble Course.
Louis Oosthuizen got to nine-under. So did Adam Scott.
Only Rory McIlroy was going backwards, the Northern Ireland star’s bid doomed by a brace of double-bogeys.
Even Tiger Woods got on the birdie bandwagon with six birdies on his last 12 holes. But after four bogeys in his first five, it was too little too late, the 15-time major winner finishing two-under and 11 shots off the pace.
Koepka’s charge slowed with a bogey at the eighth, and after two birdies and a bogey on the front nine, Woodland turned with a two-shot lead over Koepka and Rose.
Koepka pulled within one with a birdie at the 11th, giving the shot back at 12 when he failed to get up and down from a bunker.
Woodland also bogeyed the par-three 12th, but he salvaged a par after a poor tee shot at 13 to stay in front.
Trailing by two on the tee of the par-five 18th, Koepka found the fairway and ripped his second shot to the short rough behind the green, but his chip left him nine feet for birdie and he settled for a closing par.
“I played great,” said Koepka, who had taken his tally of major titles to four with his two US Open wins and back-to-back PGA Championship victories. “Nothing I could do.
“Gary played a great four days. Cool way to go out on 18, to make that bomb,” Koepka added. “He deserves it, he’s worked hard and I’m happy for him.”