The plans for LOONA had been in the works since 2014 and even earlier by creative director Jaden Jeong. The pre debut project began in 2016, when HeeJin's teaser and debut song "ViViD" were released in September and October 2016 respectively. These were followed by HyunJin, the second member’s teaser and debut track 'Around You (다녀가요)' in October and November 2016 respectively. HyunJin's single also included a duet track with HeeJin called 'I'll Be There.' In December 2016 came HaSeul's single album, with her solo debut track 'Let Me In (소년, 소녀)' and a Christmas song that featured all three currently revealed members of LOONA. Following these three was YeoJin. Her single album included her solo track 'Kiss Later (키스는 다음에)' as well as two additional tracks, 'My Sunday' and 'My Melody'. Sonically identical, these tracks only differ with a few lyrics, as well as who sings each track. 'My Sunday' is another duet between HeeJin and HyunJin, while 'My Melody' is a duet between HaSeul and YeoJin. After these 4 members made their debut, the first unit was ready for its debut. LOONA 1/3 was teased on February 5th, 2017, and made their debut on March 13th, 2017, with EP Love & Live, consisting of members HeeJin, HyunJin, HaSeul, and previously unrevealed member ViVi. Sonically, this unit dabbled in synthpop, synth funk, dance-pop, and classical music sampled into K-pop tracks. While YeoJin was originally planned for this unit, she was instead rumored to have returned to class before LOONA's debut. Additionally, she is said to be the / in LOONA 1/3. In April came ViVi's solo debut with the tracks 'Everyday I Love You' and 'Everyday I Need You' featuring HaSeul and unrevealed member JinSoul respectively. After ViVi's solo came the deluxe "repackaged" version of Love & Live, titled Love & Evil. The single "Sonatine" was released, introducing the LOONAVERSE. Kim Lip debuted in May with the track 'Eclipse' and b-side solo 'Twilight'. Previously teased member JinSoul debuted in June with the track 'Singing in the Rain' and a duet with Kim Lip titled 'Love Letter'. Choerry debuted in July with 'Love Cherry Motion' and duet with JinSoul titled 'Puzzle'. In September, these 3 members debuted in the new unit, ODD EYE CIRCLE, with the EP Mix & Match and title track 'Girl Front'. In October, the repackaged version was released, titled Max & Match with the lead single 'Sweet Crazy Love'. The sound for this unit was very different from that of LOONA 1/3, with influences from future bass, electropop, alternative dance, and dance-pop. Ninth member Yves debuted in November 2017 with lead single 'new' and b-side solo 'D-1'. Tenth member Chuu debuted in December with 'Heart Attack' and a duet with Yves called 'Girl's Talk'. Eleventh member Go Won debuted in January 2018 with 'One & Only' and a duet with Chuu called 'See Saw', featuring Kim Lip. Finally, in March 2018, final member Olivia Hye (now known as HyeJu), debuted with 'Egoist' featuring JinSoul, and a b-side duet with Go Won called 'Rosy', featuring HeeJin. These final four members debuted in the final LOONA subunit, yyxy, with the EP beauty&thebeat. The video for the lead single 'love4eva' was filmed in a Hungarian palace, and the song featured experimental pop artist Grimes. LOONA’s debut single ‘Favorite’ was released on August 7th, 2018. LOONA's first concert, LOONAbirth occurred on August 19th, and they finally debuted with the EP [+ +] and title track 'Hi High' on August 20th. The repackage to this EP, titled [X X] was released in February 2019, with the title track ‘Butterfly’. In 2020, they released the EPs [#] and [12:00], with title tracks 'So What' and 'Why Not?' respectively. These EPs marked a change in their sound, as the management within BlockBerry Creative went through major changes between [X X] & [#]. 2020 also marked the release of their first English single on the EP [12:00], 'Star'. The song went top 40 on the US Pop airplay chart, and the EP debuted at #112 on the Billboard 200 chart. In 2021, LOONA released their fourth EP [&] on June 28th, with the lead single 'PTT (Paint The Town)'. They also released their Japanese debut EP, HULA HOOP / StarSeed 〜カクセイ〜, on September 15th. They competed and placed 2nd on survival show Queendom 2 in the spring of 2022. They released their 5th EP, the summer themed [Flip That] on June 20th, 2022, and embarked on their first world tour. On November 25th, 2022, member Chuu was expelled from the group by BlockBerry Creative on the basis of "abuses of power". It was later revealed that in fact the abuse had been the other way around, with the company abusing the LOONA members. Three days later on November 28th, 9 members filed injunctions to suspend their contracts with BlockBerry Creative (excluding ViVi and HyunJin, who filed in February of 2023). A sixth EP, titled The Origin Album [0] was planned for release on January 3rd, 2023, but, due to heavy boycotts from fans, was 'delayed indefinitely'. The album has still not been released and has been effectively cancelled with all members having left the company. After leaving the company, the members followed different paths. HeeJin, Kim Lip, JinSoul, Choerry, and later HaSeul, signed with MODHAUS to redebut as ARTMS. HyunJin, YeoJin, ViVi, Go Won, and HyeJu signed with CTDE&M to redebut as LOOSSEMBLE, a portmanteau of LOONA and Assemble. Chuu signed with ATRP to debut as a solo artist. Yves also redebuted as a solo artist under PAIX PER MIL. Beloved subunit ODD EYE CIRCLE made a comeback as a subunit of ARTMS in July 2023, starting off the LOONA redebut era. Loossemble released their self-titled debut mini album in September 2023. A second EP titled 'One of a Kind' released in April 2024, and a third, titled 'TTYL', released in September 2024. On November 28th, 2024, Loossemble terminated their contracts with CTDE&M. Chuu released her first mini album 'Howl' in October 2023, and a second mini album titled 'Strawberry Rush' in June 2024. ARTMS made their debut with their 1st studio album <Dall> in May 2024, after the release of 4 "premier" singles based off the previous ARTMS releases Air Force One (ODD EYE CIRCLE), Algorithm (HeeJin Solo), and Plastic Candy (HaSeul Solo), and one fan voted song. Yves made her debut with the EP LOOP and title track of the same name featuring Lil Cherry in May 2024, and released her second EP I Did in November 2024. Throughout these projects, the members of LOONA have experimented with a hugely diverse amount of sounds and genres in their music. In the future, various LOONA members have expressed hope to rejoin together again as a full group. The members have won back legal rights to both the Korean and English version of the name LOONA, making this more possible.
LOONA members have mentioned many artists that they look up to, such as IU, HyunA, BIG BANG, 2NE1, Suzy, Sunmi, Lucia, Sejeong, Younha, Dean, MeloMance, Ariana Grande, and Paul Kim.
LOONA became the first Korean girl group in history to reach Top 40 on the pop radio airplay chart in the US with a solo song. LOONA won best Korean act in 2018 at the MTV Europe Music Awards, the Focus Award and Star Popularity Award in 2019 at the Asia Artist Awards, and the 2021 Next Generation Award at the Golden Disc Awards. They have also won 4 music shows over the course of their career. They are the K-pop girl group with the most #1 albums in US iTunes history. They charted #1 on the Billboard World Digital Song Sales chart twice, with '365' and 'SHAKE IT'. They charted on the Billboard 200 with [12:00]. They have also received critical acclaim. Despite limited coverage, they rate highly on sites like rateyourmusic.com and albumoftheyear.org, with the latter designating [X X] and Max & Match as "must hear albums", meaning over 500 people rated these albums with a score of 80/100 or higher. Additionally, its agreed among fans that their redebut era has been a highlight of their career, allowing them to try new sounds and gain more recognition without the authoritative control of their old company. Although they faced many issues with a messy agency, LOONA has still been able to gain global popularity and international acclaim.
LOONA's impact is far and wide, and at times, untraditional. Many K-pop groups have been noted as drawing from LOONA for inspiration. An example of this is iconic K-pop girl group Girls' Generation drawing inspiration from LOONA's PTT music video for their own music video. K-pop group NMIXX also drew controversy for the strong similarities between their debut video and LOONA's 'Why Not?' video. A more unconventional aspect of LOONA's impact is their lasting print on internet culture. The debut of the group put "Stan LOONA" all over the internet, along with fancams in the replies of tweets all over Twitter. Over the internet, it's still easy to find edits of Chuu with Kanye West, the iconic 'Girl Front' instrumental, mashups of songs like 'Flip That' with 'OMG' by Anzyeity / 'Long Time' by Playboi Carti with thousands of uses, and much more. Despite not being the best selling K-pop group, they continue to leave a huge impact on the industry and around the world through the internet.