On June 2, 2008, Jang tied the knot with his longtime girlfriend Kim Yeo-jin. The couple have been together since 2002; she was his Pilates instructor.[47] His close friends singer Kim Jong-kook and actor Cha Tae-hyun participated in the wedding ceremony. The couple have two sons (born in 2008 and 2009).[48] Jang has practiced Jeet Kune Do for more than 10 years and is a former professional Taekwondo athlete.