In 2004, Hu made his breakthrough role as Li Xiaoyao in the television series Chinese Paladin, an adaptation of the action RPG The Legend of Sword and Fairy. Hu also performed two songs for the series' soundtrack and that marked the beginning of his music career.

After Chinese Paladin, Hu embarked on a number of television series projects, most of which had a wuxia theme. Hu has acted in a number of films as well, including The Ghost Inside and The 601st Phone Call. In late 2008, he co-starred with Wu Chun and Charlene Choi in The Butterfly Lovers, a film based on the Chinese legend of the Butterfly Lovers. In the same year, he played the role of Guo Jing in The Legend of the Condor Heroes, an adaptation of Louis Cha's novel of the same title.