Third successive Open appearance was clinched by a tie for sixth at the Arnold Palmer Invitational in March.
Three Royal Portrush spots were on offer as part of the Qualifying Series, but of those ahead of him only compatriot Sungjae Kim was not already exempt and with Rory McIlroy and Matt Wallace, also eight under par, sure of their places as well he and Keith Mitchell had secured starts. Made the halfway cut at Royal Birkdale and Carnoustie, but best Major performance remains joint 18th place at the 2016 US Open. Turned professional in 2007, a year after appearing at the Eisenhower Trophy world amateur team championship and also winning on the Korean Tour as an amateur.
In 2009 lost a play-off to Thongchai Jaidee at the Ballantine’s Championship co-sanctioned by the European and Korean tours. Went into the event ranked 1,112th in the world and left it 380th. Enjoyed two victories on home soil in 2013, the second of them at the Kolon Korea Open by a stroke from a group including McIlroy, and came through the PGA Tour qualifying school. Led the 2017 Shell Houston Open by three after 54 holes, but was second to Russell Henley.