Choi Ji-woo was discovered through an MBC talent audition in 1994, which led to her acting debut in the MBC series War and Love in 1995. In 1997, she starred in the film The Hole, which won her Best New Actress at the 34th Baeksang Arts Awards and the 21st Golden Cinematography Awards. In 2000, she won an Excellence Award at the MBC Drama Awards for her work in Truth and Mr. Duke. The following year, she won another Excellence Award at the SBS Drama Awards for the romantic drama Beautiful Days. In 2002, she headlined the KBS2 series Winter Sonata, opposite Bae Yong-joon. The drama was a huge hit not only in Korea but also in other parts of Asia, particularly in Japan and the Philippines. It also earned Choi Ji-woo a Top Excellence Award at the 2002 KBS Drama Awards as well as the Most Popular Actress for TV at the 38th Baeksang Arts Awards. In 2004, she was once again hailed the Most Popular Actress for TV at the 40th Baeksang Arts Awards for the top-rating SBS series Stairway to Heaven, which recorded a peak viewership rating of 45.3 percent. In 2014, she reunited with her Stairway to Heaven co-star Kwon Sang-woo in the SBS drama Temptation, in which she was nominated for a Top Excellence Award at the SBS Drama Awards.

Choi Ji-woo and her non-celebrity boyfriend tied the knot on March 29, 2018. The actress gave birth to her first child on May 16, 2020.