William Kwok is the elder son of Kwok Yuen Wah, a physical education professor who introduced Wing Chun and movement science to Kwok.[8] Prior to learning Practical Wing Chun from Wan Kam Leung, Kwok trained in various martial arts systems including traditional Taekwondo, under Kim Suk Jun, a disciple of General Choi Hong Hi.[2] Kwok is credited with introducing Practical Wing Chun to America.