McIlroy and playing partners Phil Mickelson and Jordan Spieth were among the early starters hoping to take advantage of a course softened by Wednesday's rain. But that still left him ahead of the 29 players who failed to break 80, a group that included major winners Rory McIlroy (80), Keegan Bradley (81) and Martin Kaymer (83).
This is the second straight year he is No. 1 at the U.S. Open, ending a streak of six straight years with a different No. 1 at this major.
Woods appeared to be rolling along towards a round of three or four over par until a four-putt double-bogey on the par-4 14th derailed him.
Gregory wasn't the only player to suffer at the hands of the notoriously hard Long Island course, with big guns Phil Mickelson (77) Jordan Spieth (78) and Jason Day (79) also having nightmare rounds.
Johnson holed medium-length putts for birdies, a few nervy, short putts for par and picked up a bonus when his shot from a front bunker on the par-4 eighth rattled and rolled into the cup.
After Woods set the putter down behind his ball on the 10th green, he backed away when the ball moved. The was your US Open performance update.
Woods started the day with a triple-bogey seven on the opening hole, and followed it up with a bogey. Then I hit two bad putts on 1 and 2.
Saudi-led coalition keeps up Hodeidah assault before United Nations meeting
It is the first time the Saudi-led coalition of mostly Gulf states has tried to capture such a well-defended major city in Yemen . The Houthis deny they are Iranian pawns and say their revolt aims to target corruption and defend Yemen from invaders.
Quotable: "I enjoy the fight".
He'd seen the high scores of the morning starters, Woods said, and went out aiming to keep anything worse than a bogey off his card. Woods settled for an 8-over-par 78 with only one birdie. He was even par through 11 holes on Sunday before posting two bogeys, a double and a quadruple in the next four holes. I actually hit a really good flop shot.
In one stretch, Gregory - the 2016 British Amateur champ missed the cut in last year's US Open while still an amateur -double-bogeyed three straight holes.
"All I had to do after that start was shoot even par over the next 16 holes and I'd be just fine", he said. "If you hit a great shot, you're going to be rewarded". I don't think so.
From the middle of the first fairway, Woods went long over the green.
"When's the last time you heard of two guys that play golf for a living putt it off the green, uphill from 30 feet?"