Joo-won began his acting career on stage before landing a main role in the 2010 smash hit KBS2 drama Baker King Kim Tak-gu that launched him into stardom. In 2011, he starred in the KBS2 weekend series Ojakkyo Brothers, which won him Best New Actor at the KBS Drama Awards and the 48th Baeksang Arts Awards. That same year, he made his big screen debut in the action crime film S.I.U., which gave him two Best New Actor nominations. In 2012, he led the KBS2 period drama Gaksital, which earned him an Excellence Award at the KBS Drama Awards. In 2013, he played a rookie spy in MBC’s Level 7 Civil Servant and an autistic savant in KBS2’s Good Doctor. His work in both dramas scored him numerous acting recognitions. In 2015, he took home the Daesang at the SBS Drama Awards for his work in the high-rating medical drama Yong-pal, in which he was paired with Kim Tae-hee.

Joo-won enlisted for his mandatory military service in May 2017 and was discharged in February 2019. He dated singer BoA.