Things did not go so well for Tiger Woods at Muirfield Village Golf Club in Dublin, Ohio.
While Kuchar shot a four-under-par 68 in the final round, the world's top-ranked golfer finished 20 strokes back, recording his highest score since 2010.
"Yeah it happens. It happens to us all," Woods said. "Go home next week and practice."
Kuchar held off Kyle Stanley at the turn, then celebrated his two-shot victory with a handshake from host Jack Nicklaus.
"To win this tournament, to have Jack Nicklaus congratulate me is a real treat," said Kuchar, who finished the tournament at 12 under. "This is just as special as it gets."
Stanley, who bogeyed three consecutive holes early in the back nine, finished third at seven under while Kevin Chappell birdied four of the last six holes to move into second at 10 under.