[1][3] He has a younger brother named Lee Dae-yeol, who is also signed with Woollim Entertainment and is a member and leader of the boy group Golden Child which debuted in August 2017.

[4] On February 15, 2013, Lee graduated from Daekyeung University, majoring in Applied Music with fellow Infinite members Sung-kyu, L, Dong-woo and Hoya.

[8] On October 21, 2013, Lee was cast as a main character in the web drama Love for Ten: Generation of Youth with 4Minute's Son Ji-hyun.

[10][11][12] Lee and bandmates L and Sungjong formed a subgroup called Infinite F and were announced during the "One Great Step Returns" encore concert.

[18] Lee enlisted as part of his mandatory military service as an active duty soldier on March 26, 2019.