[7] In January 2016, Choi joined Produce 101 along with Kim Do-yeon and three other Fantagio trainees with the hopes of debuting in an eleven-member girl group which would promote for a year under YMC Entertainment.

[9] Both Choi and Kim rose to high ranks during the program and eventually placed 3rd and 8th respectively in the show's finale on April 1, 2016, which allowed them to debut as members of I.O.I.

[10] On May 4, 2016, I.O.I released their debut single "Dream Girls" which had its rap parts penned by Choi and Im Na-young.

The group also promoted as a seven-member unit which Choi was also a part of with Kim, releasing the single "Whatta Man" on August 9, 2016.

[16] She then released the single "Rise and Fall" together with Yoo Se-yoon, Shim Hyung-tak and Jo Kwon as part of the show's official soundtrack.

After I.O.I parted ways on January 29, 2017, and ended their contract with YMC Entertainment,[17] Choi and Kim Do-yeon filmed a reality show in the United States titled Dodaeng's Diary in LA which aired on TVING.

[18] Months later, Fantagio announced their plans to debut a new girl group, which they later revealed would be called Weki Meki.

Weki Meki's Choi and Kim and Cosmic Girls' Seola and Luda released the single "Strong" on June 1, 2018, along with its accompanying music video.

On May 4, 2021, Choi and the members of I.O.I celebrated their fifth debut anniversary with a reunion live stream show titled "Yes, I Love It!".

[30] On October 11, Choi featured on Raiden's song "It Wasn't Me" from his debut extended play Love Right Back.