1. Ji Sung is best known for his roles in the television dramas All In, Save the Last Dance for Me, New Heart, Protect the Boss, Secret Love, Kill Me, Heal Me, Innocent Defendant, Familiar Wife, Doctor John, The Devil Judge, Connection and the film My PS Partner.
Ji Sung later studied Theater and Film at Hanyang University.
Ji Sung first auditioned for the 1999 campus drama KAIST, where he met screenwriter Song Ji-na.
Ji Sung approached director Yoo Chul-yong, saying he wanted the role.
All In was a big hit, and Ji Sung's popularity rose and became known as a Hallyu star.
Ji Sung then made a guest appearance playing Bae Jong-ok's college boyfriend in "Outing", a two-episode arc written by Lee Kyung-hee for the omnibus drama Beating Heart, followed by a supporting role in Kim Dae-seung's period thriller Blood Rain.
Ji Sung enlisted on 7 June 2005, for his mandatory military service.
Ji Sung made his comeback in the medical drama New Heart, playing a cardiothoracic surgery resident.
Contrary to his cheeky, playful character, Ji Sung said that he's taciturn and shy in real life, but that the drama made him find a different side of himself.
Ji Sung then made an extended cameo as the sophisticated right-hand man of the mob boss in action noir Fate.
In 2009, Ji Sung collaborated again with writer Choi Wan-kyu and director Yoo Chul-yong of All In in the revenge drama Swallow the Sun, adapted from the novel by Kang Chul-hwa, and shot on location in Jeju Island, Las Vegas and South Africa.
Ji Sung trained hard to play the tough, strong-willed protagonist who goes to prison for his boss and later becomes involved in the city development of Jeju.
In 2011, Ji Sung starred alongside Yum Jung-ah in Royal Family, about the power plays within a chaebol family.
Ji Sung said he found the script intriguing, despite the discomfort of appearing in bed scenes.
Ji Sung next appeared in Confession, a 2014 neo-noir film that brutally explores the aftermath of three men's friendship after the death of one's mother.
Ji Sung received the Grand Prize award at the SBS Drama Awards.
In 2021, Ji Sung starred in the mystery legal drama The Devil Judge with his previous co-star Kim Min-jung who he worked together 13 years ago in the drama New Heart.
Ji Sung starred in a mystery drama called Adamas, which aired from 27 July to 15 September 2022.
Ji Sung played the roles of the twin brothers who pair up to uncover the mystery of a murder that occurred 22 years ago.
Ji Sung met actress Lee Bo-young on the set of 2004 TV series Save Last Dance for Me, and they confirmed their relationship in 2007.