Seo Eun-soo made her acting debut in the 2016 SBS series Jealousy Incarnate. In 2017, she landed a main role in the OCN sci-fi thriller Duel. That same year, she got her big break playing the twin sister of Shin Hye-sun’s character in the hit KBS2 family drama My Golden Life. She won Best New Actress at the 11th Korea Drama Awards for her work in the series. Additionally, the drama earned her Best New Actress nominations at the 31st KBS Drama Awards and the 54th Baeksang Arts Awards. In 2019, she played a passionate and righteous rookie lawyer in the JTBC legal drama Legal High. In 2020, she became part of the OCN fantasy thriller Missing: The Other Side.

Seo Eun-soo studied acting at the Korea National University of Arts.