In 2006, Song Joong-ki made his first television appearance as a contestant on KBS’ Quiz Korea, where he won second place. He then debuted as an actor in 2009 with a supporting role in the movie A Frozen Flower. In 2010, he became part of the cast of the SBS variety show Running Man, which won him the Best Newcomer in a Variety Show trophy at the SBS Entertainment Awards. That same year, he starred in the KBS2 sageuk Sungkyunkwan Scandal, which earned him the Popularity Award and the Best Couple Award with Yoo Ah-in at the KBS Drama Awards. In 2012, he led the KBS2 melodrama Nice Guy, which scored him numerous acting recognitions. Also in 2012, he played the titular character in the hit fantasy romance movie A Werewolf Boy, in which he bagged a Best Actor nomination at the 49th Baeksang Arts Awards. In 2016, he headlined the KBS2 series Descended From the Sun, opposite Song Hye-gyo. The drama was a major hit across Asia and took home the Daesang at the 52nd Baeksang Arts Awards. Song Joong-ki also collected several awards for his work in the series, including the Daesangs at the 30th KBS Drama Awards and the 5th APAN Star Awards. In 2021, he took on the leading role in the tvN dark comedy Vincenzo, in which he was nominated for Best Actor for TV at the 57th Baeksang Arts Awards.

Song Joong-ki was a short track speed racer when he was young. He enlisted for his mandatory military service on August 26, 2013 and was discharged on May 26, 2015. In early July 2017, he and his Descended From the Sun leading lady Song Hye-gyo 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