He is known for his vocal range,[4] which he has showcased in solo contributions to various Korean drama original soundtracks (OSTs) [6][7] and live stage musicals.

[10] They released their first single "Fanfare" on October 5, 2016[11] As an actor, Lee began his career as a supporting role in the interactive web drama Click Your Heart (2016),[12][13] and later played a lead character in the web drama Love in Black Hole (2021).

[13][6][7] He is best known for his acting in live stage musical productions, including Founded (2021),[14][15] Another Miss Oh (2022),[16][17] and Seopyeonje (2022).

In 2021, he released the song My Universe on the OST for the web drama Love in Black Hole,[6] in which he also appeared as a lead character.

[7] In 2022, Lee debuted his first self-composed song, Stay with Me, with live solo performances in Seoul during his group SF9's Delight concert tour.

[5] On February 13, 2023, FNC announced that Lee will enter mandatory military service on March 21, 2023, where he will attend basic training at the 3rd Infantry Division.