Curtis' 65 was the best round of the day and the best final round in the tournament's six years. The 36-hole leader, Jason Bohn, shot a 71 to finish third at 10 under.
But Bohn felt helpless when he finally checked the leaderboard at No. 17.
"I looked over and said, 'He's 18-under par? Holy cow!"' Bohn said.
None of the big names lurking near the top of the leaderboard Sunday made a charge.
Jim Furyk (7 under) and Phil Mickelson (5 under) shot 72s. Singh was out of it before he hit two tee shots in the water on No. 17 and chipped in for triple bogey. His 74 left him at 4 under.
Robert Allenby's 66 put him at 9 under and alone in fourth place. But there was no match for Kim, who became the eighth 20-something player to win this year.
"I kind of sensed that he was going for a bit of a trip," Allenby said of Kim. "I had a look on 17 just to see where he was. I knew he was going pretty good. I was playing for second."
After leaving Oklahoma following his junior year, Kim tied for second in his PGA Tour debut at the 2006 Texas Open. He earned his tour card that winter and was the youngest rookie in 2007 when he had four top-10s finishes.
But Kim didn't come close to winning and struggled with his temper and his decision-making. He decided he had to practice more and not take as many unnecessary gambles on the course.
"I think if I had won last year my practicing would have gone down even less - and there wasn't much to go down," Kim joked. "I might have been playing on the Hooters Tour. It might have been the best thing for me, just to get slapped in the face and realize that I can't win out here without practicing, giving it my all on every golf shot, every practice round."
After three missed cuts earlier in the year, Kim played in the final group at the Verizon Heritage two weeks ago, but never threatened for the win. Things changed at Quail Hollow, where Kim finished tied for seventh behind Woods last year.
Kim is the fifth first-time winner in 2008, joining Brian Gay, Greg Kraft, Andres Romero and Johnson Wagner.
"I was an immature kid last year," Kim said as he wore the winner's blue jacket. "I feel like I've grown up quite a bit and I think that helped me so much this week, so much this year and hopefully in the future."
