When Kim was young, he sung in a church choir in Seoul. He wanted to become a Christian music singer. He went to Soongsil University. He was allowed in because they had a shortage of students. It was disappointing for him enter like that, but he trained a lot to win a scholarship. He wanted a scholarship because his family was having difficulties with money. After he failed to get the scholarship, a singer named Park Sun-Joo began training Kim to sing. By chance he was signed to an agency, and he recorded part of a new song by R.ef, which was a famous rave music group in those days.