Kim Sejeong

About

In 2012, at the age of 16, Sejeong became a contestant on the competition show K-Pop Star 2. She was eliminated in the second round, but was brought back by Yang Hyun Suk as a wild card. Ultimately, she was once again eliminated in the final casting round.

In January 2016, Sejeong became a contestant on the survival show Produce 101, where she represented Jellyfish Entertainment. She ranked 2nd in the finale, thus becoming a member of I. O.

I. The group officially debuted on May 4 with their first mini album Chrysalis. On June 23, Sejeong was revealed as the fifth member of gugudan.

The group officially debuted on June 28 with their first mini album Act. 1 The Little Mermaid. As a result, Sejeong was absent from the promotions of I.

O. I's single album "Whatta Man". On November 23, as part of Jellyfish Entertainment's music channel project Jelly Box, Sejeong made her solo debut with the digital single "Jelly Box Flower Way".

On January 29, 2017, I. O. I officially disbanded following the release of their third and final digital single "Downpour".

In July, Sejeong made her acting debut through KBS2's teen drama School 2017, in which she played the female lead role. On July 10, 2018, she debuted as a member of gugudan's second sub-unit, gugudan SEMINA, with their first and only single album "Semina". On November 27, 2019, it was announced that Sejeong would release a collaboration single with Dingo, "Tunnel" on December 2, 2019.

On March 2, 2020, her first mini album, Plant, was announced, set for release on March 17. On August 10, it was announced that Sejeong would release her first digital single, "Whale", on August 17. On December 30, Jellyfish Entertainment announced gugudan would disband on December 31 after four years together.

On March 17, 2021, a teaser video was released for her comeback. Two days later, it was releaved that Sejeong would return on March 29 with her second mini album I'm. On May 11, Jellyfish Entertainment announced that Sejeong had renewed her exclusive contract with the agency.

On September 22, 2022, it was announced that Sejeong would hold her first ever Asian fanmeeting tour, titled 2022 Sejeong's Sesang Diary, from November 4, 2022 to April 23, 2023. On July 26, 2023, it was reported that Sejeong would be making her comeback in September, which was her first release in almost two and a half years. The same day, Jellyfish Entertainment confirmed the news.

On August 8, it was announced Sejeong would be releasing her first full-length album, Door, on September 4. On December 8, 2025, Kim Sejeong announced her first single album "Solar System", set to be released on December 17. On February 20, 2026, JTBC reported that Kim Sejeong had begun discussions to renew her contract with Jellyfish Entertainment ahead of its expiration.

She is also currently meeting with other agencies and considering a variety of options. Nothing has been confirmed about her departure from Jellyfish Entertainment and the agency stated that they will continue to carry out management duties for Kim Sejeong until the end of her contract period. During the Yokohama performance for her fan concert tour, she revealed she is leaving the agency.

On March 23, Jellyfish Entertainment officially announced her departure. It has also been reported that Kim Sejeong will be joining BH Entertainment. BH Entertainment officially announced Sejeong signed an exclusive contract with them the next day.