In 2008, Kim became the first American under the age of 25 since Tiger Woods to win two PGA Tour events in the same year.
He was the youngest member of the United States’ victorious 2008 Ryder Cup side, taking two-and-a-half points from four matches at the age of 23 during Europe’s defeat at Valhalla.
In Adelaide, he started the final round five shots behind overnight leaders Jon Rahm and Bryson DeChambeau.
However, Kim sank nine birdies in a round of 63 to finish top of the leaderboard on 23 under at Grange Golf Club.
Rahm ended the event with a 71, which included two birdies and a bogey, with the Spaniard three shots back on 20 under.
DeChambeau carded two birdies and four bogeys, with the American’s final-round 74 leaving him on 17 under, along with compatriot Peter Uihlein (68) and England’s Tyrell Hatton (67).
“It’s been overwhelming,” said Kim. “But I’m never not going to fight for my family.
“God gave me a talent. I was able to produce some good golf today, I knew it was coming.
“Nobody else has to believe in me, but me. And for anybody that’s struggling, you can get through anything.”