Baek began her music career in 1999, entering the South Korean dance scene with her first album Sorrow.

[10] On August 9, 2009, Baek announced a collaboration with 2PM member Taecyeon for the title track of her mini-album EGO called "내 귀에 캔디" (My Ear Candy).

They first performed the song on Kim Jung-eun's Chocolate, although the episode did not air until a week later after her official comeback on Show!

[12] She collaborated with Mighty Mouth for their comeback single "사랑이 올까요" (Will Love Come), released on March 12, 2010, along with a music video.

Her single Over Time topped various music charts on the day of its release on July 1, 2010, and Baek's greatest-hits album Timeless: The Best also sold well.

On the 17th, her Good Boy mini-album was released, including the dance title track of the same name featuring Yong Jun-hyung of B2ST.

[24] On February 16, 2013, Baek held her first solo concert in seven years at the Jamsil Gymnasium in Seoul, followed by a nationwide tour in March.

[47][48] In 2009, after suffering from a high fever and dizziness from the flu and hypotension, Baek stopped a dinner concert midway.

[50][51] The former manager, who fled to the U.S., is currently serving time in a Los Angeles jail for charges of sex with a minor, which he also recorded on video.

[13] Baek withdrew from associating with the brand in 2012 after the Fair Trade Commission fined several celebrity-run online shopping malls for posting fake user reviews.

[55] Baek filed suit against a local plastic surgery clinic that had used her photo for online advertising without her permission.

On June 24, 2013, the Seoul Central District Court found the clinic guilty of infringing on her rights for profit and awarded Baek damages of ₩5 million (US$4,320).