Better known as Kim Jun Su, the K-pop singer, songwriter, and actor uses the name Xia for his solo work. Between 2003 and 2010 he was known as Xiah Junsu while part of TVXQ!, a Korean boy band who found success in their home country and enjoyed record-breaking sales in Japan. From 2010 to 2017, he was simply known as Junsu while in JYJ, a breakaway trio comprising former TVXQ! members who achieved three Korean number one albums. His solo career ran concurrently with, and after, his work with JYJ, and brought continued success in Korea and Japan.

Xia was born in Goyang, part of the Gyeonggi-do province, in an area just beyond the outskirts of Seoul. His twin brother, Kim Jun Ho, also had musical talent and ultimately recorded as ZUNO in China and JUNO in Japan, later making songwriting contributions to Xia's solo albums. At the age of just 11, Xia was signed by SM Entertainment following a run of auditions. When he made his debut with TVXQ! in 2003, he was still in high school and, for the latter part of his time with them, he studied musical theater at Myongji University. Just prior to graduating, he released a debut solo EP in May 2010 -- under the Xiah Junsu moniker -- and he also made his debut high-profile acting appearance in the lead role of Sylvester Levay and Michael Kunze's Mozart! He was a household name by this point due to the success of TVXQ!, and audiences flocked to see the show.

He contributed to TV soundtracks Sungkyunkwan Scandal and Scent of a Woman, while JYJ made chart debuts in both Korea and Japan with C-Jes Entertainment. Xia's debut solo single for the company, "Uncommitted," and debut solo album, Tarantallegra, were both issued in May 2012, each hitting number one in Korea. Incredible followed in 2013 and hit number two before he closed out the year with the number one EP Musical December 2013 with Kimjunsu. 2014 was comparatively quiet, although his track "The Time I Loved You" appeared on the soundtrack to TV's Mr. Back. 2015 brought another Korean number two album, Flower, and a number one EP, Yesterday. It also saw Xia debut in the first Korean run of Death Note: The Musical. After the success of Xia's 2016 solo album, Xignature, he enjoyed another run in the musical in early 2017, just prior to being called for mandatory military service. Although this contributed to JYJ going on indefinite hiatus, Xia resumed solo activities in 2019, releasing the Pit a Pat EP in November 2020. It didn’t sell as well as earlier material, and proved to be his last with C-Jes after a 12-year stint. After a one-off January 2022 single released by Universal/EMI, Xia issued the Dimension EP two months later, his first output for his own company, Palmtree Island. In June, he collaborated with J-Jun -- his former JYJ bandmate -- on the single, "Rokutosei." ~ James Wilkinson, Rovi