Byun Woo-seok debuted as a model before transitioning to acting. He made cameo appearances in the dramas Dear My Friends, Weightlifting Fairy Kim Bok-ju, and Moon Lovers: Scarlet Heart Ryeo in 2016. In 2017, he starred in a supporting role in the tvN fantasy medical drama Live Up to Your Name. In 2019, he was cast in his first major role in the JTBC sageuk Flower Crew: Joseon Marriage Agency. In 2020, he acted alongside Park Bo-gum and Park So-dam in the tvN series Record of Youth. That same year, he landed his debut film role in the coming-of-age movie Soulmate.

Byun Woo-seok had already completed his mandatory military service before his debut.