Hye-jeong Kang

It was in 2005, however, that Kang established herself as a star outside of her appearance in Oldboy. The sharp-edged relationship drama Rules of Dating, in which she starred opposite Park Hae-il, proved to be an unexpected hit, and then two months later she took a small but central role in box office megahit Welcome to Dongmakgol. In a 2005 survey of influential movie producers, she was ranked among the top ten most bankable stars.

In 2006, she starred in Love Phobia opposite then-boyfriend Cho Seung-woo, as well as the Thai film Invisible Waves by rising directorial star Pen-ek Ratanaruang.

After playing the developmentally disabled daughter to veteran actress Bae Jong-ok in the 2007 melodrama Herb, in 2009 Kang starred in two unconventional romantic comedies with roles she imbued with her trademark quirkiness. She said she chose Why Did You Come to My House? hoping to "expand the realms" of her lovelorn stalker character; the director said she had written the script with Kang in mind from the beginning. In Kill Me, she played a woman who, after several suicide attempts, hires a professional assassin (Shin Hyun-joon) to kill her, but he falls in love with her instead.

On October 26, 2009, Kang married Tablo of hip hop group Epik High while she was three months pregnant. The couple's first child, a daughter named Haru, was born on May 2, 2010.

In 2010, Kang appeared in her first stage play Proof, portraying the role of Catherine, who worries whether she has inherited all of her mathematician father's genius and lunacy.

After making the little-seen 2007 KBS drama Flowers for My Life with Cha Tae-hyun, Kang returned to television in 2011 in MBC's Miss Ripley, a tale of one woman (Lee Da-hae) who spins a web of love, ambition and lies. Originally touted as a drama with four lead roles, Kang later expressed dismay and disappointment with her drastically reduced screen time.

Kang left her previous management agency YG Entertainment (which is also her husband's label) in 2013, and signed with C-JeS Entertainment. She then played a small role in E J-yong's mockumentary Behind the Camera, and wrote the lyrics to "Good Thing," one of the songs on Bobby Kim's album Mirror.

Kang starred in her second stage play Educating Rita in late 2014, about the relationship between a hairdresser and a middle-aged university lecturer. She also played a supporting role in the film How to Steal a Dog.

In 2017, Kang played a psychiatrist in the sci-fi thriller Lucid Dream. She made her return to television in December 2017 with office comedy series Jugglers.