{ ✧ Prior to the group's debut, several members were already involved in the entertainment industry. Jeno had filmed various commercials as a child. Jisung was previously a child actor with roles in films such as Boys, Be Curious (2012), No Cave (2013), and Go, Stop, Murder (2013) and a member of Poppin' Hyun Joon Kids Crew. Chenle was active in the Chinese music scene as a child singer; he released three albums, held solo concerts in China, and participated in Chinese programs, including China's Got Talent. Mark was the first member to join SM Entertainment in 2012, after passing SM Global Auditions in Canada. Haechan was cast through the SM Saturday Open Casting Audition in 2013, Jisung and Jeno were cast through the company's casting system, and Jaemin was cast by the staff while doing volunteer work and successfully passed the audition. In July 2015, Renjun was selected through the SM Global Auditions in China. Chenle was the last member to be chosen in 2016, just three months before NCT Dream's debut.
{ ✧ Mark, Jeno, Haechan, Jaemin, and Jisung were previously part of SM Rookies , the pre-debut team of trainees under SM Entertainment. As part of SMRookies, in October 2014, they appeared on Mnet - produced Exo 90:2014 , a show starring labelmates Exo , where they performed dances to K-pop songs from the 1990s. From July to December 2015, the five boys were Mouseketeers at Disney Channel Korea's The Mickey Mouse Club, where they performed music and dance, played games, and participated in skits. SM Rookies Boys finally held their own concert, SMRookies Show, which took place in Seoul in September 2015 and then expanded to Bangkok .Thailand in February 2016. NCT was first announced in January 2016 by Lee Soo-man at a presentation outlining the group's plans to debut different sub-units around the world. Mark previously debuted with the group's first unit, NCT U rotation , on April 4, 2016. On July 7 of the same year, Mark and Haechan debuted in NCT's second sub-unit, Seoul- based NCT 127 . They debuted again with five new members—Renjun, Jeno, Jaemin, Chenle, and Jisung—as NCT Dream, NCT's third sub-unit, which was announced on August 18, 2016.