2012–2016: Beginnings and rising popularity '' Korea in 2015 Seo took on
bit parts in various television series, before making his acting debut as with a supporting role in
SBS' drama
The Suspicious Housekeeper. His first major role was in the 2014
romantic comedy series Cunning Single Lady, for which he won the Best New Actor award at the 7th
Korea Drama Awards. He has then appeared in television dramas
What Happens to My Family? (2014–2015),
Splendid Politics (2015), and
To Be Continued (2015), as well as films
My Love, My Bride (2014) and
Summer Snow (2015). In 2014, Seo joined the SBS variety show
Roommate as a cast member. He also appeared on
Law of the Jungle as a guest. Seo's breakout role came in 2016 as a talented pianist in the college romance drama
Cheese in the Trap. The same year, he starred in his first leading role in
tvN drama
Entourage, the Korean remake of the American television series
of the same name.
2018–present: Leading roles In 2018, Seo starred in KBS's science fiction drama
Are You Human? where he played double roles as a wealthy heir and robot. The same year, he starred in romance comedy drama
The Third Charm. In 2019, Seo starred in OCN's thriller drama
Watcher as a policeman. He was cast in the
JTBC romance drama
When the Weather Is Fine, which aired in the first half of 2020. In 2022, Seo starred in
Disney+ (
Star) thriller drama
Grid as an employee of the Grid Bureau. which aired in the first half of 2025. == Personal life ==