The 51-year-old, who plays in the Saudi-backed LIV Golf League, began the day five adrift of leader Fujita at Rhode Island's Newport Country Club, but his four-under par 66 final round left him deadlocked with Fujita after 72 holes on 13-under 267.
Fujita, 55, struggled in Monday's restart to the storm-halted final round with three bogeys in a four-hole stretch to fire a closing 71.
Bland and Fujita were level after a two-hole aggregate playoff after each parred both holes, then both made bogeys on the sudden-death par-4 18th hole the first time before playing the closing hole once again.
Bland dropped his approach into a greenside bunker while Fujita was short of the green after finding rough off the tee. Bland nearly holed his blast from the bunker, hitting the flagstick and setting up a tap-in par putt.
When Fujita could not get up and down, missing a 20-foot par putt, Bland had his second senior major title in a row after the Senior PGA Championship in May.
"I was just hoping going into the PGA that I was good enough to contend," Bland said. "I knew if I played the way I know I can play, it should be good enough to be able to compete. But with two majors... I'm at a loss for words."
The Englishman became the 12th player to win his US Senior Open debut and only the third to win his first two senior major starts after Arnold Palmer in 1980-81 and Alex Cejka in 2021.
"Definitely disappointed I didn't hit the ball as well as I have all week," Fujita said. "I was really hoping to take that trophy home."
Bland's victory earned him a berth in next year's US Open at Oakmont.
