E.SO

Following the departures of Subin, Iera, and Nayeon earlier in the month, on January 23, 2015, Seoyul was revealed as the newest member of Berry Good. She made her official debut as a member on February 9 with the digital single "Because of You". In October 2017, Seoyul became a contestant on the survival show MIXNINE.

She was eliminated in episode 7 after ranking 139th place. On February 22, 2021, Seoyul announced via Instagram that she would be leaving Berry Good following the expiration of her contract. On May 7, she was revealed to have signed to A.