[2] The title song of the new album was "Trinity", a ballad sung with a shouting-like singing style.

His first major role was as Kim Jaewon's rival for Eugene's affections in Wonderful Life.

He also starred in KBS daily drama You Are My Destiny opposite of Girls' Generation member, Im Yoona.

Lee performed as male lead Daniel, rotating with Um Ki-joon, Ahn Jae-wook, Song Seung-hyun of FT Island and Lee Sungmin of Super Junior in the musical Jack the Ripper from July 5 to August 14, 2011, at Chungmu Arts Hall.

[3] In September 2013, it was announced that Lee had been cast as Fiyero Tigelaar in the Korean production of the musical Wicked.