After debuting in 2016, they broke into the domestic mainstream in 2017 with "Cherry Bomb", now recognized as one of their signature songs, and received greater international attention following the release of "Kick It" in 2020.

[11] Lee announced that the label planned to debut a new boy group with an "unlimited" number of members, in alignment with their "culture contents" strategy.

[12][13][14] On July 1, 2016, NCT 127 was announced as the second sub-unit, a Seoul-based, multi-national boy group that would promote actively in South Korea.

The name "NCT 127" combines the acronym for Neo Culture Technology with the number "127", the longitude coordinate of the city of Seoul.

[25][26] Taeyong then joined fellow trainees Johnny, Mark, Donghyuck, Yuta and Jaehyun in the Mnet-produced reality show Exo 90:2014.

[31][32] Along with other SM Rookies trainees, the members starred in their first reality show series, titled NCT Life, in the same month.

[51][52] The lead single also received positive reviews from music critics, hailed by Dazed Digital as one of the top 20 best K-pop songs of 2017, and a fan favorite.

[53] Similar to their previous releases, the unit began their promotion cycle for "Limitless" and "Good Thing" on M Countdown on January 5.

[55] The release marked NCT 127's breakthrough, with "Cherry Bomb" being their first single to enter the Gaon Digital Chart, peaking at number forty-seven,[56] and earning the group their first music trophy.

[63] In December, after signing with Avex Trax, NCT 127 was confirmed by SM Entertainment to make their official Japanese debut in spring of 2018, accompanied by their first showcase tour.

[66] The group released their first Japanese EP Chain via Avex Trax on May 23, 2018, which debuted and peaked at number two on the Oricon Albums Chart.

[69] Along with the release of a new teaser video, the label confirmed that member Jungwoo would officially join the lineup for their upcoming first full-length album, titled Regular-Irregular, on October 12.

[71][72] In association with their role as one of Apple Music's Up Next artists, album promotions included a group performance of an English version of the lead single "Regular" and "Cherry Bomb" on Jimmy Kimmel Live!

The digital EP contained an English version of "Cherry Bomb", remixes for "Fire Truck" and "Regular," and the original song "What We Talkin' Bout" featuring American singer Marteen.

Due to his preparations to debut with China-based sub-unit WayV, member Winwin did not join the group's promotional activities for the release of the repackage.

[89] The group featured on Jason Derulo's single "Let's Shut Up & Dance", which was released on February 22, alongside labelmate Lay Zhang.

[93] 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 were the third K-pop act to perform on the former.

[104] They released their first live album, Neo City: Seoul − The Origin, on October 24,[105] and performed at the 2019 MTV Europe Music Awards in Seville, Spain on November 3, becoming the first K-pop group to do so.

[109] After the announcement of Jungwoo's return, the group released their second Korean studio album, Neo Zone, on March 6, 2020, featuring lead single "Kick It".

[130][131] As of November 3, 2021, Sticker and Favorite have sold a combined total of 3.58 million copies, making it the best-selling album by an artist under SM Entertainment.

[138][9] On October 6, NCT 127 held a sold-out concert at the Crypto.com Arena in Los Angeles, California, as part of the North American Leg of Neo City – The Link.

[140] The show, titled Neo City: Seoul – The Link+, featured a new set list that included tracks from their fourth studio album 2 Baddies.

NCT 127 continued touring in Asia in November and December 2022, playing shows in Jakarta, Indonesia and Bangkok, Thailand.

[141] In January 2023, they continued their Neo City – The Link tour in North America, performing in Chicago, Houston, and Atlanta.

In the same month, they held shows in São Paulo, Brazil, Santiago, Chile, and Bogotá, Colombia, with the lattermost becoming the first large-scale K-pop concert in the country.

[142] On May 27, NCT 127 headlined the K-pop music festival M(a)y Concert 2023, at the Queen Sirikit National Convention Center in Bangkok, Thailand.

[143] On July 16, they held their seventh anniversary fanmeeting, titled Once Upon A 7uly, at the Jamsil Indoor Stadium in Seoul, South Korea.

[145] Containing four episodes, it focuses on the members' childhoods, their personal lives prior to debut, and their perspective on international success.

They frequently collaborate with American producer Dem Jointz, who has composed many of their lead singles alongside South Korean songwriter Yoo Young-jin.

[152] NCT 127's choreography has been noted for its intensity and complexity, and the members' synchronized dance moves across different styles have received praise.