Sung was in medal contention leading into the final lap of the 1500 m event there, when a crash between him and a teammate led to his finishing in 5th place.

Sung began speedskating in elementary school at the behest of his parents, who hoped that it would help make him stronger.

[1] Sung's career in the short track speed skating world cup has been a successful one.

He and his South Korean teammates also won the World Team Championships in 2009, having earned third place the previous year and second in 2007.

[1] In the first of these events, the 1500 m, Sung was among the three leading skaters, all South Koreans, going into the final lap when he was taken out by his teammate Lee Ho-Suk who attempted to pass him and both collided and slid into the wall.