The child actor practically grew up onscreen, playing the roles of an adorable son in several MBC series including See and See Again in 1998 and Ajumma (also known as Housewife's Rebellion) in 2000.

As he entered his teenage years, he played the younger versions of male protagonists in dramas such as Damo (2003), Emperor of the Sea (2004) and Stairway to Heaven (2003) — the last his breakout role.

[4] Of note is Baek's performance as a young marathoner in the four-episode Running, Gu (2010), his acting calm and gravitas in the eight-episode drama special White Christmas (2011),[5][6][7] and his leading man turn in the youthful romance Melody of Love (2013).

[9] Baek enlisted on January 2, 2018, as a Marine Coast Guard to fulfil his mandatory military duties.

[12] Baek Sung-hyun and his daughter, Seo-yoon were cast members of the KBS2's variety show The Return of Superman.