Lee was selected by Anyang SBS Stars in the 2004 KBL draft as the second overall pick.

He was traded to Seoul Samsung Thunders for Joo Hee-jung at the end of the season.

During the team's successful run to the 2005–06 championship, he was a core member of a formidable squad that included Kang Hyuk, Lee Kyu-sup and Seo Jang-hoon.

Due to Lee Kyu-sup and Seo's height (both were over 6 feet and 6 inches tall), the team's quick and physical offensive style was nicknamed "high altitude basketball" by the press.

[5] At the 2009 FIBA Asia Championship, Lee helped the Koreans to a seventh-place finish while averaging a team-leading three assists per game.