The lineup for NewJeans was reportedly finalized in March 2022 under ADOR (All Doors One Room), a subsidiary record label of Hybe Corporation.

[15] "Cookie" is a pop-R&B track with pulsing synthesizers, a fluttering bassline, and faint 808 kicks;[8] its bridge incorporates Jersey club elements.

[8][16] Carmen Chin of NME gave three out of five stars, stating that "with their musical ability and the label's bold artistic vision, NewJeans have managed to lay some solid groundwork for a bright future as trailblazers".

[8] Joshua Minsoo Kim of Pitchfork wrote, "NewJeans' launch has been the most elaborate campaign in K-pop this year", stating that the EP is "a plush and stylish collection of '90s and '00s-indebted R&B production".

[10] In December 2022, Rolling Stone ranked it as number 46 in their list of best 100 albums of 2022, describing the EP as "a unique sound and fresh visual component, leaning heavily into a Nineties pop aesthetic that suits this band well and guarantees replays".

[31] After the release of New Jeans, all tracks immediately ranked high on major South Korean domestic music charts such as Melon, Genie, Bugs!, and Vibe.

[36] Following the release of New Jeans, NewJeans held a live countdown on YouTube on the same day to introduce the extended play and communicate with their fans.