Ji Sung (born Kwak Tae-geun on 27 February 1977) is a South Korean actor. He is best known for his roles in the television dramas All In (2003), Save the Last Dance for Me (2004), New Heart (2007), Protect the Boss (2011), Secret Love (2013), Kill Me, Heal Me (2015), Innocent Defendant (2017), Familiar Wife (2018), Doctor John (2019), The Devil Judge (2021) and the film My PS Partner (2012). Early life Kwak Tae-geun's parents were both educators, and they expected him to also enter the teaching profession. But in his sophomore year in high school, his father bought him a VCR and the first movie he rented was Rain Man. Dustin Hoffman's acting left such an impression on him that he decided to become an actor, despite his father's objections. He later studied Theater and Film at Hanyang University. Career 1999–2002: Beginnings Ji Sung first auditioned for the 1999 campus drama KAIST, where he met screenwriter Song Ji-na. Song took an interest in the young upstart and wrote a new character for him, leading to his acting debut. Upon the suggestion of his then-manager, he began using the stage name Chae Ji-sung, then decided to drop the surname "Chae," and became known simply as "Ji Sung" After several minor roles, he began playing bigger parts, notably in the television dramas Wonderful Days (2001) and Sunshine Hunting 2002), as well as the North-South romantic comedy film Whistling Princess (2002). 2003–2004: Breakthrough Ji was then cast in the 2003 gambling drama All In. Producers were having difficulty casting the second male lead because most actors were afraid to be compared to lead actor Lee Byung-hun. 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. Wanting to challenge himself, he next appeared in his first period drama The King's Woman, playing Gwanghaegun of Joseon. In Save the Last Dance for Me (2004), he played a rich amnesiac businessman who falls in love with a girl running a bed and breakfast who nurses him back to health (played by Eugene). He 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 (2005), followed by a supporting role in Kim Dae-seung's period thriller Blood Rain (2005). 2005–2007: Enlistment Ji