In August 2017, JYP Entertainment (JYPE) officially announced their new reality survival show with the goal of launching a male idol debut project. More details and teasers were released in the next two months, including the show's title, Stray Kids. Prior to its premiere on October 17, JYPE released Stray Kids' first music video for a song titled "Hellevator", which was later released as a digital single. Two members, Lee Know and Felix, were initially eliminated from the group but returned to the final nine-member line-up.
Stray Kids (Korean: 스트레이 키즈; RR: Seuteurei kijeu; often abbreviated as SKZ) is a South Korean boy band formed by JYP Entertainment through the 2017 reality show of the same name. The group is composed of eight members: Bang Chan, Lee Know, Changbin, Hyunjin, Han, Felix, Seungmin, and I.N. Originally a nine-piece group, member Woojin left due to undisclosed personal reasons in October 2019. Stray Kids released their pre-debut extended play (EP) Mixtape in January 2018 and officially debuted on March 25 with the EP I Am Not.
Along with the launch of Stray Kids' official website, JYPE announced the release of the group's pre-debut extended play (EP) titled Mixtape. It contains seven tracks co-written and co-composed by the members, including "Hellevator" and other songs that they performed on the show. The EP, along with the performance video of its second track "Beware" (Korean: Grrr 총량의 법칙), was released on January 8, 2018, while the performance video of "Spread My Wings" (Korean: 어린 날개) was uploaded online a week later. It debuted at number two on the Gaon Album Chart and Billboard World Albums chart.
In February 2018, before Stray Kids' official debut, the nine members were announced as new models for Jambangee Jeans for their spring collection. In June, they were selected as an exclusive models for Ivy Club for the 2018 fall semester. The next month, Stray Kids partnered with Minute Maid Sparkling and were selected as promotional models for CGV "Youth Brand Festival" five days later. On September 19, Stray Kids began endorsing Lotte Duty Free, and on October 16, Stray Kids became new models for the Korean sportswear brand Pro-Specs. In June 2019, Stray Kids was chosen as the newest ambassador of Talk Talk Korea Contest, and on June 18, they were appointed as honorary ambassadors by the Korean Culture and Information Service, Ministry of Culture, Sports and Tourism.
On March 5, JYPE announced Stray Kids would make their third comeback on March 25, 2019 with the release of their fourth EP Clé 1: Miroh in commemoration of the first anniversary of the group's debut. The group earned their first music show win on April 4 on M Countdown for the album's lead single, "Miroh." On June 19, they released their first special album Clé 2: Yellow Wood, along with lead single "Side Effects" (Korean: 부작용), between the American and European legs of their first world tour.
On October 28, 2019, Woojin left Stray Kids and terminated his contract with JYP Entertainment for undisclosed personal reasons. From February to July 2021, Hyunjin was on hiatus due to bullying allegations against him but has since resumed regular activities with the group in August.
On June 17, Stray Kids released their first studio album Go Live alongside lead single "God's Menu", including on the tracklist the Korean versions of "Top" and "Slump" and previously released singles “Gone Days" and "On Track". Go Live became the group's best-selling album at the time, debuting atop the weekly Gaon Album Chart and selling 243,462 copies by the end of the month to reach number five on the monthly Gaon Album Chart. The album was certified platinum by the Korea Music Content Association (KMCA) in August 2020, the group's first album to achieve this. "God's Menu" became the group's first single to appear on the weekly Gaon Download Chart, debuting at number 144. Three months later, the group reissued their first studio album as In Life on September 14. During promotions, the group received two music show wins: once on MBC M's Show Champion and once on Mnet's M Countdown. Lead single "Back Door" was recognized by Time magazine at eighth on its list of the 10 Best Songs of 2020, the only song by a Korean act on the list, and described as "an artful Frankenstein that’s as catchy as it is complex".
In November 2020, Stray Kids was chosen to become Shopee Indonesia's brand ambassador for the 11.11 Big Sale and 12.12 Birthday Sale. On February 1, 2021, Stray Kids was chosen to become new models for Clio Cosmetics. In June 2021, the group was chosen to become endorse the Japanese clothing brand Wego and as ambassadors for the Korea Pavilion of Expo 2020 Dubai. In September, the group was chosen to become new models for the cosmetic brand Nacific, and the group's sub-unit Danceracha (Lee Know, Hyunjin, and Felix) appeared in campaigns for Italian brand Etro's unisex Earthbeat sneaker. In 2022, the group was selected as muses for the clothing brand Mahagrid's 2022 Summer T-Shirt Campaign, as well as ambassadors for Philippine clothing brand Bench.
The group released their second Japanese single "Scars"/"Thunderous" (Japanese ver.) on October 13. The single entered at number two on both Oricon Singles Chart and Billboard Japan Hot 100, selling over 180,000 CD copies. A Christmas-themed "special holiday" single album titled Christmas EveL was released on November 29, featuring both the title track and "Winter Falls" as lead singles. It peaked atop Gaon Album Chart, selling over 743,000 copies in 2021 alone, and was certified double platinum by KMCA. The group concluded the year with the digital release of SKZ2021, a compilation album including re-recorded versions of previous songs and the Korean version of "Scars", on December 23.
Stray Kids held their first official fan meeting, Stray Kids 1st #LoveStay 'SKZ-X' on February 20, 2021, via V Live and their first Japanese fan meeting—STAYing Home Meeting—for the first anniversary of their Japanese debut on March 18. The group collaborated with Swedish producer Alesso and Chinese DJ Corsak on the Korean version of the song "Going Dumb" for the mobile game version of PUBG, released on March 19. The song debuted at number 13 on Billboard's Hot Dance/Electronic Songs, the group's first appearance on the chart.
At the 2020 Mnet Asian Music Awards, it was announced that Stray Kids would be joining Ateez and The Boyz on the inaugural season of Kingdom: Legendary War, a Mnet boy group competition show; BtoB, iKon and SF9 were later confirmed as participants as well. On May 28, 2021, the group released a song for the final round of the competition titled "Wolfgang", which marked the group's first appearance on the main Gaon Digital Chart, at number 138. They won the program on June 3, earning them their own reality show and a Kingdom Week special show for their comeback.
Stray Kids surprise-released the third single for their Mixtape Project, "Mixtape: Oh", on June 26. It debuted atop Billboard World Digital Song Sales, their first number one on the chart. The group released their second studio album Noeasy on August 23. It debuted atop Gaon Album Chart, selling over 1.1 million copies as of August 2021 and certified million by the KMCA, making them first act under JYP Entertainment to sell more than one million copies of an album. Lead single "Thunderous" peaked at number 33 on Gaon Digital Chart and number 80 on Billboard Global 200 and earned six wins on music programs. The accompanying music video on YouTube reached 100 million views in 55 days after release, the group's fifth and fastest video to reach this mark.
On February 10, 2022, it was announced that Stray Kids signed with Republic Records for promotions in the United States as part of JYP Entertainment's strategic partnership with the label, alongside labelmate Itzy. The group held their second fan meeting 2nd #LoveStay 'SKZ's Chocolate Factory' from February 12–13 at Olympic Hall; the second day of the meeting was broadcast on Beyond Live.