Six shots ahead at the start of the final round, Clark's final act was two putts from just outside 50 feet for par that gave him a three-over 73 and a one-shot victory over Burns.
Clark, who won the 2023 US Open at Los Angeles Country Club, became the first wire-to-wire winner of the US Open since Martin Kaymer at Pinehurst No. 2 in 2014 as he triumphed at four under 276 on Sunday.
This sure didn't feel like that. His lead was down to a single shot after just five holes, and the stress followed him the rest of the way.
The clincher for Clark was one of his worst drives of the day on the par-5 16th. He gouged that out and narrowly cleared a bunker. His 8-iron barely stayed on the back of the green. And he rolled in a 30-foot birdie putt that gave him a two-shot lead with two holes to play.
It was a signature moment with muted applause. The gallery rooted against him all day, putting all their support behind final group partner Scottie Scheffler and his bid for the career grand slam.
World No.1 Scheffler had his own share of mistakes and never got closer than three shots all day as he shot 71 and tied fourth, four shots back.
One fan was ejected when he shouted, "Don't choke, Wyndham" when it was Clark's turn to hit on the fourth tee and there were cheers for his poor shots.
"I get it — they were rooting for Scottie," Clark said. "Grand slams only happen a few times. He's going to get it. He's the best player in the world. But today it's my day."
Burns closed with a 67, his second chance in as many years to win the US Open. He missed two birdie chances on the final two holes, but what hurt just as much was a three-putt bogey on the 15th when he was trying to catch Clark.
Qualifier Tom Kim, who like Scheffler celebrated a birthday on Sunday, was on the fringes of seriously contending until he fell back with a bogey on the 17th and shot 70 to finish third, three shots back.
Clark had the highest final round of a US Open champion since Graeme McDowell closed with a 74 to win at Pebble Beach.
No matter. The 32-year-old American has two US Open titles, and two wins in the last month.
Clark capped off quite a turnaround from a year ago. He was playing poor and looking angry, throwing a driver at the PGA Championship that made a marshal flinch, and then bashing in his locker at storied Oakmont Country Club after missing the cut in the US Open last year.
"New York didn't really like me — I love you guys," Clark said at the closing ceremony.
"But I get it. Some of it's self-deserved. I did some unfortunate things last year that I really regret, and I've been sorry multiple times and I'm still sorry, so hopefully I can win you guys over eventually."
Later he reflected on his two major triumps.
"The first one was kind of just the breakthrough of knowing I can do it," Clark said. "And then this one was a lot of redemption. Last year was so tough, a terrible year. I left this place in shambles, and it's amazing what a year can do. I'm leaving here this Sunday as a champion, and I'm just so blessed."
