Song Hye-gyo got her start in the entertainment world as a model for a school uniform company when she was in high school. She then made her acting debut as a minor character in the 1996 KBS2 series First Love. In 2000, she landed her first leading role in the KBS2 romance melodrama Autumn Fairy Tale, which shot her to pan-Asian fame. She was named Most Popular Actress for TV at the 37th Baeksang Arts Awards for her work in the series. She went on to solidify her success with the 2003 SBS gambling drama All In, which won her a Top Excellence Award at the SBS Drama Awards. In 2004, she reached another milestone in her career when she was paired with Rain in the hit KBS2 romantic comedy Full House, which earned her another Top Excellence Award at the KBS Drama Awards. In 2007, she played the titular character in the biographical drama film Hwang Jini. In 2013, she raked in acting nominations and wins for her performance as a blind heiress in the SBS drama That Winter, the Wind Blows. In 2016, she starred in the top-rating KBS2 series Descended From the Sun, which bagged the Daesang at the 52nd Baeksang Arts Awards.

Song Hye-gyo trained as a figure skater until eight grade. In early July 2017, she and her Descended From the Sun leading man Song Joong-ki announced that they were engaged. The couple tied the knot in a private ceremony on October 31, 2017 amid huge public interest. Twenty months later, it was revealed that Song Joong-ki had filed for divorce from Song Hye-gyo. Their divorce was finalized in July 2019. Song Hye-gyo also previously dated actors Lee Byung-heon and Hyun Bin, whom she co-starred with in All In and The World They Live In, respectively.