Missing just one green in regulation and two fairways in the final round, Langer outlasted fellow World Golf Hall of Famer Vijay Singh by one stroke to claim the only major on the Champions Tour that had eluded him. Langer became the only player to win all five senior majors.
By closing with a 4-under-par 68 for a 72-hole total of 18-under 270, Langer earned his ninth senior major title to break a tie with Jack Nicklaus. Langer had equaled Nicklaus last week after finishing first in the Tradition.
It's the second time in his career Langer has won consecutive senior majors.
"It means a great deal to win two majors at age 59," Langer said. "I'm not sure many people have done that. To surpass Jack's record of eight majors out here is pretty neat. I'm a good friend of Jack's, and I think very highly of him, and whenever you can do something just similar to what he's achieved, you've done something pretty special."
After being deadlocked with Singh for nine straight holes, Langer went in front to stay with a birdie at the 454-yard par-4 16th, the last hole on the scenic back nine that runs along the Potomac River coastline. His tee shot found the fairway again, a specialty from one of the more accurate drivers on the senior tour, and his approach settled within 12 feet of the pin.
Langer's putt turned right and disappeared into the cup for his fifth birdie in the final round.
Singh, meanwhile, had driven into the left rough and muscled the ball out and onto the green. His 15-foot birdie rolled a foot past, and the 54-hole leader made the comebacker for par.
Langer picked up another shot at the par-3 17th. Both players had their tee shots come to rest roughly 30 feet from the hole, with Langer lagging inside a foot and tapping in. Singh putted to four feet but missed his par attempt on the left edge.
That two-stroke swing proved significant when Singh closed with a birdie on 18. Langer's birdie putt went less than a foot past the hole, and immediately after making par, he raised both arms in triumph.
Standing just off the green to greet Langer was his daughter, Christina, who flew to the tournament from Seattle to surprise her father and watch him win his 32nd event on the Champions Tour.
"That was a cool moment and totally unexpected," Langer said. "It actually put a little more pressure on me because I figured, heck, if she's here, I better win this thing. We don't want to finish second or third or anything worse, but it was really fun having her out there, and now we're going to celebrate a little bit this evening together."
Different approaches to the 534-yard par-5 13th yielded birdies for Singh and Langer, whose tee shot found the center of the fairway. His approach landed just short of the front of the green, and he elected to putt from there, with the ball stopping 15 feet from the hole.
Singh's drive had landed in the rough approximately 230 yards to the pin. He went for the green anyway, and his approach embedded on the lip of a bunker, allowing for relief. Singh chipped within two feet, placing pressure on Langer to make his long putt.
His attempt rolled on line into the cup. Singh made his putt to get to 17 under as well; he made birdie at the 13th during every round of the Champions Tour's longest running major.
Singh began the day with a one-shot lead and soon pushed it to two with a birdie at the 386-yard par-4 second. Deft wedge play allowed Singh to land his approach within two feet. Langer's second shot came to rest pin high some six feet from the cup, and his birdie try missed just left.
Langer got one back on the next hole, a 539-yard par-5 that he also had birdied each of the previous two days. This time, Langer sent his third shot within four feet and sank the putt to jump-start his round. Singh then dropped a shot with a bogey at the 210-yard fourth, missing a short putt to leave both players at 15 under.
"Probably I over-read some putts, if anything," said Singh, whose 33 putts in the final round were tied for 67th in the field. "I should have gone with instincts more than just over-reading it. The putt on 17, I just over-read the first one, and I was too concerned about the line than the speed, but the stroke feels good. It's just the ball just would not cooperate today."