The American entered round four with a one shot lead over Justin Rose but it was two time defending champion Koepka who emerged as his nearest challenger as he chased a fifth Major in his last nine starts.
Koepka signed for a 68 to become the first player in U.S. Open history to record five consecutive rounds in the 60s but Woodland showed nerves of steel in a 68 of his own that gave him a 13 under total and a three shot win.
Woodland did not achieve a single top ten in his first 27 Majors but after two in consecutive US PGA Championships, he is now in the winner’s circle with a first European Tour victory as the U.S. Open produced a home champion for the fifth consecutive season.
“I’ve worked hard my whole life,” he said. “I’ve been surrounded by amazing people and I always just wanted to be successful.
“I didn’t know what it was, what I was going to do. I fell in love with golf and it’s transcended to today.
“I’ve just always believed in myself. No matter what I’ve done, from when I was a young kid, I always believed I would be successful. I believed I would play professional sports. I always believed I would be in this moment.
“We put a lot of work in this year into becoming a more complete player. I can play different golf courses. People probably growing up said U.S. Open wouldn’t suit me because I’m a long hitter, I’m a bomber.
“Coming to Pebble Beach, on top of that, it’s a shorter golf course and I went out and proved, I think to everybody else, what I always believed, that I’m pretty good.”
Rose put an approach to seven feet at the first to join the lead but he bogeyed the second and with Woodland birdieing from seven feet and adding another from similar range on the next, the lead was three.
Koepka sandwiched an incredible par after going right off the second tee with approaches to inside ten feet at the first, third and fourth, and a 22 foot putt on the fifth brought a fourth birdie of the day and cut the lead to two.
Rose got on the par five sixth in two for a birdie that moved him back within two but that would be his final gain of the day as it became a two horse race.
Koepka found nasty rough with his second and sand with his third on the eighth to drop a shot but Woodland sent his tee shot on the ninth left and the gap was back to two at the turn.
A Koepka birdie at the 11th after an approach to 11 feet meant it was a one shot tournament and while Woodland saved par at the same hole after a remarkable shot from thick rough to 13 feet, both of the leading contenders bogeyed the par three 12th after missing the green.
A birdie at the 14th after two excellent opening shots extended the lead to two and while Woodland played a nervy tee shot on the penultimate hole, he produced a lovely deft chip and saved par.
The last was played in conservative fashion but Woodland holed a 30 footer for a closing birdie and an ultimately convincing win.
Rose dropped shots on the eighth, 12th, 13th and 15th to slip back, while Schauffele carded a 67, Rahm took one more blow and Reavie finished with a 71.
Norway’s Viktor Hovland took low amateur honours as he finished at a record score of four under alongside English trio Matthew Fitzpatrick, Matt Wallace and Danny Willett.