Jackie Chan's nickname for Hyun Jin Park is "Mong Cha Cha", because Park likes to walk around in a daze when he is not working. "Mong Cha Cha" is a Cantonese term for someone who walks in his own world.
Started as a stuntman in Korean films before Jackie Chan gave him a spot on his stunt team.
Studied tae kwon do at a young age in his hometown of Daejong, Korea.