In early 2000, she appeared in episode 7 of Song Ji-na's omnibus drama Love Story, titled "Insomnia, Manual and Orange Juice."

Kim achieved mainstream stardom in 2002, with her Cinderella-esque leading role in Glass Slippers, about two sisters who were separated as children and unknowingly encounter each other as adults.

Kim returned to television in 2007 with In-soon Is Pretty, playing the titular character who went to prison for unintentionally killing someone in high school, and after serving her sentence, must face prejudice as an ex-con while rebuilding her life.

[7] In 2009, she was cast in a small supporting role (or extended cameo) as the hero's tough-but-stylish older sister in the highly popular Boys Over Flowers, adapted from the Japanese manga Hana Yori Dango.

[8] Then in the legal drama Partner, Kim played a widow-turned-lawyer whose passionate idealism clashes with her colleague's (Lee Dong-wook) detached cynicism.

Also featured as a photo spread in Sure magazine, the shoot promoted environmental awareness by emphasizing Canada's natural backdrops, and showing Kim's green practices such as using canvas instead of plastic bags and unplugging unused electrical appliances.

[4][11] 2010 was a difficult year for Kim, with the deaths of three of her loved ones in close succession: her friend, actor Park Yong-ha committed suicide on June 30,[12] the production company executive who'd cast her in The Land committed suicide on July 1 because of financial difficulties, and her father Kim Tae-beom died on July 7 after a long illness.

She donated the condolence money collected for her father's funeral and a portion of her book sales to Good Neighbors, which was used to build libraries in 11 orphanages in impoverished areas of Dhaka.

Kim said, "I literally fled to Bangladesh after a series of personal tragedies, but I was consoled by the smiles of children who are living in these dire conditions.

[15] Then in Dummy Mommy (2012), she played a fashion magazine editor with a genius-level IQ who is embarrassed by her developmentally disabled mother (Ha Hee-ra).

Critics praised Kim's versatility, as Lady Jo transforms from a naive young girl into an ambitious royal concubine who uses her beauty and wiles on King Injo in her lust for power.

Ji accepted the role first, and I knew that many people would want to see us reunite on screen, so it didn't take me long to decide to join the series.".

[32] In 2023, Kim starred in the Netflix sci-fi film Jung-E directed by Hellbound director Yeon Sang-ho, in the title role of a legendary mercenary who is also the subject of brain-clone testing.