From 2003 to 2009, Park performed as a member of the best-selling K-pop boy band TVXQ. In July 2009, Park and two of his TVXQ bandmates, Jaejoong and Junsu, filed a lawsuit against their South Korean agency S.M. Entertainment. Through their lawyers, the members stated that the 13-year contract was excessively long, schedules were held out without the confirmation or permission of the members, contract terms have been extended and changed without their knowledge or consent and that the group's earnings were not fairly distributed to the members. After TVXQ's Japanese label announced a group hiatus in early 2010, they formed a new three member group initially known as JUNSU/JAEJOONG/YUCHUN in Japan.