U-Know Yunho debuted as the leader of the South Korean boy group TVXQ in 2003. In October 2004, they released their first Korean studio album Tri-Angle, which featured the hit lead single Hug. In March 2006, they penetrated the Japanese market with the album Heart, Mind and Soul. In 2009, while the group was at the peak of their popularity, TVXQ members Jaejoong, Yoochun, and Junsu sued SM Entertainment over the supposedly unreasonable length of their exclusive contract. The three eventually left the group and formed the trio JYJ. In 2011, TVQX’s remaining members U-Know Yunho and Choi Kang Changmin made a comeback as a pop duo with the Korean album Keep Your Head Down. In 2015, U-Know Yunho released his first Japanese solo extended play U Know Y.

U-Know Yunho officially made his acting debut in 2009 with a leading role in the MBC series Heading to the Ground. In 2013, he joined the main cast of the SBS drama Yawang, which won him the Most Popular Actor citation at that year’s Seoul International Drama Awards. In 2014, he became part of the MBC fusion sageuk Records of a Night Watchman, which earned him an Excellence Award nomination at the MBC Drama Awards. In 2017, he starred opposite Kyung Su-jin in OCN’s Meloholic.

U-Know Yunho enlisted for his mandatory military service in July 2015 and was discharged in April 2017. He is fluent in both Korean and Japanese.