On April 9, 2012, Pledis revealed that a brand new member would be added to the group. The following day, the new member was officially revealed to be Kaeun and details regarding a Korean comeback in June were revealed.
Kaeun made her first appearance with the group at After School's first Japanese concert. She performed the group's hit song "Bang!" and drums performance of "Let's Do It" with the group. There she was introduced to the fans by E-Young as After School's new member.
Kaeun made her official debut with the group on June 21, 2012 performing their new single "Flashback" on M! Countdown.
On 6 July 2015, PLEDIS Youtube Channel posted a video with Kaeun with a DJ debut.
On 31 July, Kaeun made an appearance in Kye Bum Zu's GIVE IT 2 U MV.
Kaeun was part of the show Produce 48, and unfortunately was eliminated during the finale after reaching the 14th place.
Pledis Entertainment announced that After School member Kaeun would be leaving After School & the label, Releasing the last single under Pledis Entertainment "I'll Remember" in July 6, 2019.
- [2013.09.18] Heaven (Reckochoku Digital Single)
- [2013.23.08] Nylon
- Kaeun spent her junior high school days in Japan, and her fluent Japanese skills became a huge benefit to the group, since they also promote their music in Japan.
- She is said to have the most powerful vocal talent among all the Pledis Entertainment trainees.
- Kaeun also plays the flute.
- She is currently a vocalist for the group, however she was previously a rapper when member Nana was absent.
- She shares a room with fellow member E-Young.
- She is very close to E-Young.
- Kaeun appeared in the 16th episode of Roommate alongside Lizzy.
Youngest member of After School