On May 5, 2015, she became a contestant on JYP's newest survival show, SIXTEEN. She finished the survival in 3rd place, hence becoming a member of the girl group TWICE. They officially debuted on October 20, 2015 with their first mini album, The Story Begins
On June 22, 2016, SBS revealed that Jeongyeon, alongisde her sister Gong Seung Yeon and actor Kim Min Su, would be the new MCs for the music show Inkigayo. She worked on the music show until January 22, which was her last episode. On that day, Jeongyeon posted a message on Twitter to thank fans for supporting her.
She was originally set to debut in the girl group 6mix.
She officially changed her name from "Yoo Jeong-yeon" in third grade because she was teased for her birth name "Yoo Kyung-wan", which was considered too boyish.
On her first try, she failed the JYP audition. She became a trainee after passing the JYP Entertainment’s 6th Open Audition on March 1, 2010.
The leader of Twice was decided by anonymous voting. Jeongyeon was in 2nd place.
The name Jeongyeon means 'virtuous' and 'beautiful' in Korean.
Her sister is actress Gong Seongyeon and they hosted Inkigayo together, and their father is a chef.
She is ambidextrous, but her left hand is dominant. She can throw and write with her right hand, while eaing food with her left.
She has 2 dogs: a white Pomeranian named Bbosongie and a poodle named Nanan.
In Gallup Korea's annual music polls which interview 1,500 people between the ages 13-29, Jeongyeon was voted the 15th most popular idol in 2016, the 12th in 2017, and the 17th in 2018. Among Twice, alongside Nayeon and Tzuyu, she is one of the members who ranked in the top 20 idol list for three consecutive years.