Lee was selected for the 2005 FIFA World Youth Championship in Netherlands. However, for most matches, he remained in the bench, not playing a single match in the group stage, while his team-mate Park Chu-young made good impressions. He was confirmed in the Summer Olympics squad in 2006, and became the most valuable player in the squad to qualify for the Olympic games. He was selected for the 2007 AFC Asian Cup, and also capped for the South Korea under-23 team in qualification for the 2008 Summer Olympics.