Shrugging off a bad putt on the 72nd hole, Kim parred the first hole of a playoff with Vaughn Taylor to win the Houston Open on Sunday for his third PGA Tour title.
Kim and Taylor were tied at 12-under 276 after Kim missed a 6-foot par putt in regulation on the water-lined 18th hole to settle for a 2-under 70.
Not long ago, Kim said he would've mentally unraveled.
"Two years ago, that bag may have been in the water," Kim said. "I might not have had clubs to go to the playoff. But I just feel calm out there, I feel no sense of urgency. It's something that's happened naturally and not something that's been forced.
"I'm comfortable with who I am out there. I found my identity."
Taylor finished with a 68. He needed a victory to qualify for the Masters next week in his hometown of Augusta, Ga.
"Hugely disappointed," Taylor said. "It's a tough pill to swallow."
Charl Schwartzel (67) and Graham DeLaet (68) finished a stroke back at 11 under. Shaun Micheel (65) was two shots behind and Kevin Stadler (68) and Houston resident Jeff Maggert (70) finished four behind.
The 24-year-old Kim won for the first time since the 2008 AT&T National. He also won the Wachovia Championship in 2008. But after a 2009 highlighted more by injuries than victories, Kim caught himself in a negative spiral that was making things worse.
He finished 39th on the money list after reaching No. 6 in 2008, then re-dedicated himself to his practice routine and worked on his mental approach. And now he heads to the Masters riding four straight top-25 finishes.
"I just look back at last year, after the season was over, I was just complaining about everything," Kim said. "I felt like I deserved to win a golf tournament without trying. That's not how it is.
"I've put in a lot of hard work, so I feel like when I'm out there, I know I'm going to do well. Having that confidence really has propelled my game, I feel like, to a different level."
Kim and Taylor played No. 18 again in the playoff and Kim made a routine 4, two-putting from 30 feet. Taylor hit a bad drive, played out of the greenside bunker and came up short on his 18-foot par putt.
"I was reading it to go just a little left, and I got consumed with the line," Taylor said. "It's a must make. Kind of embarrassing to leave it short."
The event went to a playoff for the second straight year. Paul Casey beat J.B. Holmes last year with a bogey on the first extra hole after Holmes drove into the water.
Taylor played in the group ahead of Kim and forced a playoff with an 18-foot birdie putt on the 18th hole. He backpedaled as the ball curved toward the hole and flipped his putter in the air when it dropped.
Kim, who shared the third-round lead with Bryce Molder, birdied the first hole on Sunday and maintained the outright lead until the 18th. He hit his approach into the greenside bunker, blasted out to 6 feet and missed to the right.
He struggled with his tee shots all weekend, but found the fairway on the playoff hole. Taylor hit the bunker on the right off the tee and couldn't recover.
Kim hit only 23 of 56 fairways in four rounds, the fourth-lowest total for a winner since 1983.
"I was in some spots on the golf course I never thought I could possibly see," Kim said. "But I got out of those with pars and birdies and feel very confident going into next week."
Earlier in the day, Phil Mickelson finished 2 under after an eventful 71. He double-bogeyed three of his first 10 holes, then reeled off six straight birdies to match the best streak on tour this year. Matt Every birdied six consecutive holes in Phoenix.
During his hot stretch on the back nine, Mickelson pulled a special guest out of the gallery to carry his bag. Dr. Tom Buchholz, a radiation oncologist at the M.D. Anderson Cancer Center in Houston, is treating Mickelson's wife and mother, Amy and Mary, who were both diagnosed with breast cancer last summer.
Buchholz wasn't totally inexperienced. He was working in the pro shop at the Westchester Country Club after college in 1984 when he caddied for Allen Miller in the PGA Tour's Westchester Classic. Miller tied for 10th.
"It was a story we talked about over the many hours and weeks and months we've been together in the hospital," Mickelson said. "We went 3-for-3, three birdies."
Light rain fell in the morning, but the tournament avoided a weather delay for the first time since 2005.