So Ji-sub debuted as a jeans model in 1995 before landing his first acting role in the MBC youth sitcom Three Men and Three Women in 1996. His career took off when he joined the main cast of SBS’s Glass Slippers in 2002. The following year, he bagged his first leading role in the SBS sageuk-fusion drama Thousand Years of Love, which won him an Excellence Award at the SBS Drama Awards. In 2004, he appeared in the SBS romance melodrama Something Happened in Bali, which gave him the Baeksang Most Popular Actor for TV trophy. He next starred in KBS2’s I’m Sorry, I Love You, opposite Im Soo-jung. He received the Best Actor honors at the 41st Baeksang Arts Awards for his work in the series. In 2008, he acted alongside Kang Ji-wan in the action film Rough Cut, which earned him critical acclaim. In 2009, he took home a Top Excellence Award at the SBS Drama Awards for Cain and Abel. In 2012, he was given another Top Excellence Award at the SBS Drama Awards for Ghost. In 2013, he was paired with Gong Hyo-jin in the hit SBS series Master’s Sun, which scored him his third Top Excellence Award at the SBS Drama Awards. In 2015, he played a personal trainer to Hollywood stars in KBS2’s Oh My Venus. In 2018, he clinched the Daesang at the MBC Drama Awards for his performance in My Secret Terrius.

A hip-hop lover, So Ji-sub also ventured into rapping. In March 2012, he released his debut extended play Corona Borealis. This was followed by the mini-albums 6PM… Ground in 2013 and 18 Years in 2014.

So Ji-sub was a professional swimmer prior to his debut in the entertainment industry. He enlisted for his mandatory military service in February 2005 and was discharged in April 2007. In 2020, he married former TV presenter Jo Eun-jung, who is 17 years his junior.