Se7en debuted as a singer with the album Just Listen in March 2003. It spawned four singles including Come Back to Me, which won him Best New Artist at the Golden Disc Awards and the Mnet Music Video Festival. In 2006, he released his first Chinese and Japanese albums titled Must Listen and First Se7en, respectively. The said albums propelled him to pan-Asian fame. In 2007, he made his acting debut as the lead star in the MBC series Goong S, which was a spin-off of the hit 2006 romantic comedy Goong a.k.a. Princess Hours. In 2009, he made his U.S. debut with the single Girls featuring American rapper Lil’ Kim. In October 2016, he released the mini-album I Am Se7en after a long hiatus.

Se7en enlisted for his mandatory military service in March 2013. Just months later, he and Mighty Mouth’s Sangchu were found guilty of visiting illegal massage parlors while on official leave. They were given 10-day military jail sentences for violating several military regulations. Se7en was officially released from military in December 2014. He is currently in a long-term relationship with actress Lee Da-hae. He also previously dated actress Park Han-byul.