Born in South Korea but raised in California, Kim attended the University of California Berkeley where he played on the golf team alongside Max Homa.

Became the first men's golfer from Cal to win the Jack Nicklaus Award after he was named by the Golf Coaches Association of America as the receipient in 2013.

Won the Haskins Award that same year after voting from players, coaches and the media. Later in 2013, he earned low amateur honours at the U.S. Open, finishing in a share of 17th at Merion.

Turned professional in 2013 and earned full membership of the PGA TOUR for the first time for 2016.

Won his first PGA TOUR title at the 2018 John Deere Classic, setting a tournament record as he won by eight strokes.

Claimed his maiden DP World Tour title at the 2025 FedEx Open de France, becoming the first American to win France's national open since Barry Jaeckel in 1972.