Upon graduation from high school in 1999, he chose to play college baseball at Korea University instead of turning pro directly.

Although Lee immediately became one of the most reliable and consistent hitters in the team, he failed to make an impact with the Unicorns as a catcher due to his defensive deficiencies.

In the 2006 season, he finished second in batting average (.322), tenth in RBI (66) and sixth in hits (135), and was selected to the All-Star team and won his first KBO League Golden Glove Award.

After the season, he was selected for the South Korea national team and competed in the 2006 Asian Games held in Doha, Qatar.

In August 2008, he competed for the South Korean national team in the 2008 Summer Olympics held in Beijing, China, where they won the gold medal in the baseball tournament.

[1] On May 18, 2017, he won the game against Hanwha by hitting the first pinch-hitter-ending grand slam in the KBO league against Jung Woo-ram.