 While attending Holy Spirit High School, a friend signed him up for an audition with Brothers Entertainment without Joo's knowledge.The company has discovered several Korean-Americans who wish to pursue an entertainment career in South Korea.After several months of training, he was sent to SM Entertainment in South Korea, and on December 9, 1999, made his debut as one of the two members of Fly to the Sky, along with Hwanhee, at the age of 17.