In August 2009, at age 17, An became the youngest-ever winner of the U.S. Amateur when he defeated Ben Martin 7 & 5 in the 36-hole final at Southern Hills Country Club in Tulsa, Oklahoma. He made his PGA Tour debut in March 2010 at the Arnold Palmer Invitational, two weeks before playing in The Masters. “Ben” turned professional in 2011 and earned a spot on the Challenge Tour via three stages of qualifying school. The South Korean moved up to the European Tour in 2014 courtesy of a win at the Rolex Trophy and claimed his maiden European Tour title at the 2015 BMW PGA Championship. In 2016, he earned enough money as a non-member to gain a PGA Tour card for 2016–17 and finished 42nd in the FedEx Cup standings this year to retain his card. An will be making his third appearance at the WGC-HSBC Champions, his best result is a T-19.