[2] He debuted as an actor on MBC's drama Find Me in Your Memory as Jo Il-kwon.

[3] Along with fellow member Kim Woo-seok, he took a hiatus from UP10TION group activities and competed as a trainee on Produce X 101.

[4] He finished the program ranking 11th, but because of the show's rule of the X position, he did not make the final lineup of X1.

M, set to be released in 2021, as the role of Gil Mok-jin, a second year student studying Psychology at Seoyeon University.

[citation needed] Lee returned with his third extended play Scene26 on April 5, 2021, accompanied with the title track "5K".

[15] Later on February 28, it was announced that Lee would be leaving TOP Media, as well as Up10tion, after deciding not to renew his contract which expired on March 11.

[18] On November 27, 2024, Lee was ruled exempt from mandatory military service due to congenital heart defect.