[5] Between 2013 and early 2015, Jeongyeon was expected to become a member of a new JYP girl group alongside fellow trainees (now Twice bandmates) Nayeon, Sana, and Jihyo;[1][6] however, the project was cancelled.

[5][10] In October 2015 Jeongyeon officially debuted as a member of Twice with the release of their first extended play (EP), The Story Begins and its lead single "Like Ooh-Ahh".

[21] According to former reporter Lee Jin-ho, Jeongyeon's subsequent weight gain was likely due to steroid medications commonly used after disc surgery.

[26] On 18 August 2021, JYP Entertainment announced that Jeongyeon would be taking a second hiatus due to panic and anxiety disorder.

[27] She resumed activities as a member of the group in February 2022, beginning with the North American leg of Twice 4th World Tour "III".