NCT 127 is the second sub-unit and Seoul-based unit of the South Korean boy group NCT. The unit debuted on July 7, 2016, with their first extended play NCT #127, featuring seven members: Taeyong, Taeil, Yuta, Jaehyun, Winwin, Mark, Haechan. Johnny and Doyoung later joined in December 2016, followed by Jungwoo in September 2018. Their name is a combination of the acronym for Neo Culture Technology which is their meaning for their unlimited members, and the number 127, which represents the longitudinal coordinate of Seoul.

Pre-debut: SM Rookies and NCT

All ten members of NCT 127 were originally part of SM Rookies, a pre-debut training team maintained by SM Entertainment. In January 2016, SM founder, Lee Soo-man, announced plans for a new boy group with several different units to be based in cities around the world. NCT 127 was officially announced on July 1, consisting of previously debuted NCT U members Taeyong, Taeil, Jaehyun, and Mark, along with three newly debuting members: Yuta, Winwin, and Haechan.

2016: Debut and new members

NCT 127 made their official debut with NCT #127 on July 10, 2016. The EP debuted at number two on the Gaon Album Chart, and topped the chart by the third week of its release. It also charted at number two on the Billboard World Albums Chart. Their debut performance took place on Mnet's M Countdown where they played the lead single "Fire Truck" and "Once Again." On December 5, NCT 127 released the dance performance version of their song "Good Thing,” and on December 20, they released the music video for "Switch,” featuring members of the SM trainee group, SR15B. On December 27, SM Entertainment announced the addition of two new members to NCT 127: Johnny and NCT U's Doyoung.

2017: Limitless and Cherry Bomb

On January 5, NCT 127 released the music video for "Limitless." It was the title track of their second EP, Limitless, which was released on January 9. The EP debuted atop Korea's Gaon Album Chart and the Billboard World Albums Chart. NCT 127 released their third EP Cherry Bomb on June 14, with the lead single of the same name. The next day, the group performed the songs "Cherry Bomb" and "0 Mile" for the first time on M Countdown. Billboard and Idolator both later named “Cherry Bomb” one of the best K-pop songs of the year.

2018: Empathy, Japanese debut, new member, Regular-Irregular and Regulate

On March 14, 2018, NCT 127 released the single "Touch” as part of NCT 2018 Empathy, a full-length studio album that brought together all active units of NCT, and grouped them under the collective name NCT 2018. On May 23, NCT 127 released their Japanese debut EP Chain via Avex Trax. It peaked at number two on the Oricon Albums Chart. In August 2018, it was announced NCT 127 will participate in the single "Let’s Shut Up and Dance," as part of a global collaborative tribute to Michael Jackson. On October 12, NCT 127 released their first full-length album, Regular-Irregular, which debuted at number 86 on the US Billboar200. The album also marked the addition of NCT U’s Jungwoo to the NCT 127 lineup, which now totals 10 members. The album release was led by a performance of English version of the lead single, "Regular" and "Cherry Bomb" on Jimmy Kimmel Live! which also marked the group's first appearance on U.S. national television . NCT 127 followed through with extensive promotions in America, including a performance at ABC's Mickey’s 90th Spectacular TV special on November 4.

On October 21, NCT 127 released a digital EP, Up Next Session: NCT 127, exclusively through Apple Music. It contains alternative versions of previous singles "Fire Truck," "Cherry Bomb," and "Regular," as well as an original track, “What We Talkin’ Bout”, which features Marteen.[29] On November 23, NCT 127 released the repackaged edition of Regular-Irregular, titled Regulate, along with the lead single "Simon Says". It was announced that Winwin would not be participating in the comeback activities in order to prepare for his debut with WayV. On December 19, 2018, it was announced Haechan would be taking a hiatus from the group due to injuries.

2019: First world tour, Awaken and We Are Superhuman

On January 2019, NCT 127 held their first concert tour, Neo City – The Origin. NCT 127 will extend their tour to North America, with twelve tour dates on April and May 2019.[ On March 18, the group released "Wakey-Wakey" as the lead single to their first Japanese studio album, Awaken, which was released on April 17. In April 2019, NCT 127 signed with Capitol Music Group and Caroline Distribution for a worldwide distribution deal with SM Entertainment; CMG and Caroline will provide distribution and marketing for the group for several territories worldwide. Ahead of the North American leg of their tour, the group made appearances on Good Morning America and Strahan and Sara on April 18; they are the third K-pop act to perform on the show. In the same month, the group announced their fourth EP, We Are Superhuman, which was released on May 24, 2019; the group continued as nine, as Winwin is currently promoting with WayV. The group performed the EP's lead single, "Superhuman", at their appearances on Good Morning America and Strahan and Sara. They also performed the song during an appearance on The Late Late Show with James Corden on May 14. The group will have a Japanese variety show, NCT 127 Tell Me JAPAN!, which will air on dTV from June 9. We Are Superhuman debuted at number eleven at the Billboard 200 albums chart with 27,000 album units, becoming their second entry in the chart. The EP also became their second number one album at the World Albums chart.

On the 4th of July, NCT 127 X Ava Max will release a colaboration digitial single called "So Am I". - Wikipedia