AJ Debuted With His Single Album "First Episode A New Hero" And Promoted With The Song "Dancing Shoes". His First Ever Debut Stage Was April 4 2009 On M!CountDown. Before AJ Debuted He Was Trained In JYP Entertainment For 4 Years And Was Transfered To Cube Entertainment. AJ Finished Promotion Of His Album With The Song "눈물을 닦고" Wipe The Tears . AJ Has Now Been Transferred To The Boygroup B2ST Who Debuted October 2009.