Fifteen of Crush's singles have peaked in the top ten on the Gaon Digital Chart, with ten of Crush's singles also becoming top five hits including "Just", "Beautiful", "Don't Forget", "Bittersweet", "Let Us Go", and "Rush Hour".

[2] Raised in Seoul, he began listening to R&B and hip hop music at a young age and aspired to become a singer.

Dynamic Duo's debut album Taxi Driver left a "deep impression" on him, which inspired him to begin rapping.

[3] He began making music during his first year of middle school with a friend and sending demos to the group's record label Amoeba Culture.

Nicknamed "Shi Syeob" (시셥), he wrote the moniker "C-sub" in English as a tentative stage name.

[2] While taking a break from school, Crush sent Zion.T his demos after meeting at a hip hop party.

[15] In January 2016, Crush released the single "Don't Forget" featuring Girls' Generation's Taeyeon.

][18] Crush also went on to win Best Vocal Performance - Male Solo at the 18th Mnet Asian Music Awards.

In May 2020, it was announced that Crush had asked Joy of Red Velvet to feature on the lead single of his next album.

[35] On August 23, 2021, Crush was confirmed to be in a relationship with singer and actress Joy, whom he had collaborated with during the previous year.