In 2013, He was cast into SM Entertainment. He has featured in SMROOKIES events such as SMTown Week, before he was formally introduced on October 13, 2015. On January 26th, Taeil released the song “Because Of You” for the soundtrack of the series The Merchant: Gaekju 2015
2016–present: Debut with NCT U, NCT 127, and NCT 2018
On April 9, 2016, he officially debuted as a member of NCT, in the unit NCT U, with the single "Without You".
On July 7, 2016, he debuted in the sub-unit NCT 127 with the mini-album, NCT #127.
On March 14, 2018, he joined NCT's first full album, NCT 2018 Empathy as part of their NCT 2018 project.