Tang Joon-sang started out as a musical actor before making his screen debut in the 2014 EBS children series Pluto Squad. In 2018, he played the young counterpart of Go Kyung-pyo’s character in the action-drama film Seven Years of Night and also appeared in tvN’s You Who Forgot Poetry. His career breakthrough came in 2019 when he played a North Korean soldier in the hit tvN romantic comedy Crash Landing on You. In 2021, he starred as a 20-year-old boy with Asperger syndrome in the Netflix series Move to Heaven, which won Best Drama Series at that year’s Asian Academy Creative Awards. He then joined the 2021 SBS sports drama Racket Boys, which gave him the Best Young Actor trophy at the SBS Drama Awards.

Tang Joon-sang’s father is a Chinese Malaysian while his mother is a South Korean.