Kwak Tae-geun, better known as Seong Ji, is a South Korean actor who is best known for his roles in the TV dramas All In (2003), Save the Last Dance for Me (2004), Secret Love (2013) and Kill Me, Heal Me (2015). He won several awards such as Best New Actor at MBC Drama Awards (2001), New Star Award at SBS Drama Awards (2001), and so on.
Seong Ji first auditioned for the 1999 campus drama KAIST, where he met screenwriter Song Ji-na who took an interest in the young upstart and wrote a new character for him, leading to his acting debut. He graduated from Hanyang University with a degree in Theater and Film.
Seong Ji married actress Lee Bo-young in 2013 and the couple welcomed their first child, daughter Kwak Bo-bae born on June 12, 2015.