Ji Sung

Ji Sung (지성; born Kwak Tae-geun on February 27, 1977) is a South Korean actor signed to Surpass Entertainment. Born in Yeongdeungpo, Seoul, his path to acting was shaped by a single VCR rental: watching Dustin Hoffman in Rain Man convinced him to pursue performance despite his educator parents' expectations. He studied Theater and Film at Hanyang University and made his debut in the 1999 campus drama KAIST, where screenwriter Song Ji-na wrote a new character specifically for him. He dropped the surname from his original stage name "Chae Ji-sung" and became simply Ji Sung.

Over two and a half decades of television, he has built a reputation for inhabiting psychologically complex characters. His early career was anchored by romantic leads including All In (2003) and Save the Last Dance for Me (2004), before expanding into genre territory. His widely acclaimed performance in Kill Me, Heal Me (2015) required portraying a character with dissociative identity disorder across seven distinct personalities -- widely regarded as one of Korean television's most technically demanding performances. He continued with the legal thriller Innocent Defendant (2017), the time-slip rom-com Familiar Wife (2018), medical drama Doctor John (2019), and the dystopian courtroom series The Devil Judge (2021).

His 2024 return in Connection -- playing a drug-dependent detective unraveling a conspiracy among childhood friends -- earned Drama of the Year at the SBS Drama Awards. In early 2026, he led The Judge Returns (판사 이한영) on MBC alongside Park Hee-soon and Won Jin-ah, a courtroom thriller based on the Naver webtoon by Lee Hae-nal, which aired through February 14, 2026. He is married to actress Lee Bo-young; together they have two children.