Byun Woo-seok debuted as a model in 2014 before transitioning to acting in 2016 with cameo appearances in several TV series. In 2019, he bagged his first major role in the JTBC sageuk Flower Crew: Joseon Marriage Agency. The following year, he acted alongside Park Bo-gum and Park So-dam in the tvN series Record of Youth. In 2021, he played a rebellious crown prince in the KBS2 sageuk Moonshine, which won him Best New Actor at the KBS Drama Awards. In 2022, he appeared in the Netflix coming-of-age romance drama film 20th Century Girl, which gave him Best New Actor nominations at the 59th Baeksang Arts Awards and at the 32nd Buil Film Awards. He was once again nominated for Best New Actor, this time at the 59th Grand Bell Awards for the romantic drama film Soulmate. In 2023, he took on his first villain role in JTBC’s high-rating series Strong Girl Nam-soon. In 2024, he experienced a surge in popularity after starring in the tvN time-slip romance drama Lovely Runner, alongside Kim Hye-yoon.

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