She appeared in the television drama series Over the Rainbow, and in films such as Dasepo Naughty Girls, The Accidental Gangster and the Mistaken Courtesan and The Villainess.

[6][7] She next starred as the lead actress in Hanoi Bride, a two-part SBS drama aired during the Chuseok holidays to commemorate the 30th anniversary of the Vietnam War.

[9] Kim auditioned for a part in the 2006 KBS drama series Hello, God, and after impressing director Ji Yeong-soo with her "intense determination," was handed a leading role as confidence trickster Seo Eun-hye.

[10] During filming she expressed self-doubts, saying, "I used to cry two or three times everyday [sic] when the shooting began because I felt that I was a rubbish actress," and with a tight schedule that allowed her less than two hours of sleep per day, was reported to have collapsed on set.

[2] Later that year, she appeared in MBC drama Over the Rainbow as aspiring pop singer Jeong Hee-su, a part which required her to sing and master difficult breakdance moves.

She said she had found it difficult performing a historical role, but was helped by consultations with director Yeo Gyoon-dong and studied traditional Korean dance for two months.

[13] In February 2008, Kim was announced as the female lead in Park Chan-wook's Thirst, in a part that required numerous adult scenes with co-star Song Kang-ho.

[15] Thirst topped the South Korean box office during its opening weekend with over one million admissions,[16] and was invited to the 2009 Cannes Film Festival where it won the Jury Prize.

E J-yong had contacted actors that he's personally close to and offered them the roles, and most of them accepted without pay based on their friendship and loyalty to him, Kim included.

[31] Kim returned to television in 2013 in the KBS period epic The Blade and Petal set in the Goguryeo dynasty, her first TV drama in seven years.