Kim, 21, shot a three-under-par 69 on the final day at Sawgrass to finish on 10 under and replace Adam Scott as the youngest victor.
Fellow internationals Ian Poulter (71) and Louis Oosthuizen (73) tied for second at seven under. He missed 10 greens in regulation on Sunday yet didn't make a single bogey. That was rarely in doubt over the back nine.
Kim was also the fourth different leader at the of each round, proving once again this course tested every golfer's abilities.
The Players Championship - Is it a major, is it just a really big event, or is it a separate entity that doesn't fit into a specific category?
"I feel like I'm still dreaming that I won this championship", Kim said. "That's when he had the least amount of pressure on himself", said Kim's caddie, Mark Carens.
"I still can't believe that I'm the champion and I'm the youngest champion for this championship", said Kim.
"I've given him some champagne but he tells me he prefers red wine so he'll get some of that as well", Poulter told Sky Sports.
He did not have a top 20 all year.
It has still been a remarkable week for Poulter, who only played 13 tournaments in 2016 because of a foot injury. Holmes plummeted 40 spots to a tie for 41st at 3-over par.
Taking home a nice $1,890,000 for his spectacular performance, Kim also climbed up to a career high 28 in the world rankings to announce himself as one of golf's most promising young talents.
World number 11 Scott languished on day four, dropping two shots on his opening nine holes to sink to 1-under-par.
A run of nine pars in succession on the back nine was enough for Kim to seal victory, while Spain's Rafa Cabrera Bello produced a far more spectacular finish to claim a tie for fourth with Stanley.
Kim sank a 24-foot birdie putt at the par-4 seventh to seize the lead and sank an 18-foot birdie putt at the par-5 ninth to reach 10-under for a two-stroke advantage. He already had accomplished what he needed with a second-place finish, knowing his PGA Tour playing privileges are now good for the remainder of the year. The only saving grace of the season was a third-place finish at the Cleveland Open. The Queenslander started the final round poorly with two bogies in his first nine holes, but he bounced back with four back nine birdies to card a two under 70.
"I saw it kick off the bank of the bunker and I was a bit anxious at the beginning because I kind of felt that it shot a little too fast", Cabrera Bello said.
He was playing on a major medical extension from a foot injury past year and had 10 tournaments to earn enough money or FedEx Cup points to keep full status. Aside from being cut at January's Farmers Insurance Open, this is the first time Johnson has finished outside the top 10 in the 2017 calendar year. But his smooth swing looked back on point while manoeuvring around TPC Sawgrass' risky layout. Even though Kim only hit eight greens in regulation, he went six straight holes on the back without facing a par putt over 2 feet. You're not in the tournament, you get in at the last minute, and you play your best golf.
Kim's triumph saw him replace Australia's Adam Scott as the youngest ever victor of the Players Championship, which is regarded as golf's unofficial fifth major. He never got flustered, and he never stepped outside the zone he seemed to exist in throughout the final 36 holes.
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