 FC Seoul at the time signed a handful of youngsters this way, with the most prominent ones being Lee Chung-yong himself, Ko Yo-han, Koh Myong-jin and Song Jin-hyung.He was a Substitute in the 2004 League Cup, In 2006, he debuted in the K League.For the next several years, Lee honed his skills in the FC Seoul reserves alongside close friend and international teammate Ki Sung-yueng.