He was cast into SM Entertainment in 2012, discovered by street scouts in front of his school. On December 9, 2013, he was introduced as a member of the pre-debut trainee team SMROOKIES.
In 2014, he participated with other fellow NCT members on the show Exo 90:2014, where they performed songs from the 90s. From January 21 to July 1, 2015, he, & NCT-co member, Doyoung were MCs on MBC Music's Show Champion. In July 2015, he and Ten both competed in Hope Basketball All-Star.
In December 2015, he performed Aladdin - A Whole New World in Disney Channel Korea's The Mickey Mouse Club with former SMRookies member Herin.