Center midfielder who joined Beijing Guoan in 2014 and became a member of the South Korean national team in 2008.
He debuted professionally for Ulsan Hyundai Horang in 2004.
He scored 19 goals in 112 matches for FC Seoul from 2010 to 2013.
He was born in Incheon, South Korea.
He and Lee Chung-yong became teammates on the South Korean national team.