I Don't Like Mondays.

The band name "I Don't Like Mondays." was chosen because the members liked the idea of using a sentence to describe the band.[5] The band has stated that they truly dislike Mondays, and they consider it to be a weekly holiday.[3]

The band was formed in 2012 in Omotesando, Tokyo.[6] Yu was intending to be the manager of a new band when he met Kenji and Shuki, who had worked together in a previous band. Choji joined after the band's initial guitarist dropped out.[7]

Their first album Play was released in September 2014 by Nippon Coumbia,[8] with the band playing a number of festivals the same year, including Tokyo Crazy Kawaii Taipei[9] and J-Music LAB 2014 in Hai Day.[10] The music video for "Perfect Night" was released in July, followed by a remix of the song in December by DJ Baby-T.[11]

In January 2015, they released the double-A-side single "We Are Young"/"Super Special",[8] which included three EDM remixes of previously-released songs. The artwork and jacket photo were produced with art direction from the band members,[12] and the single was selected as one of Japan's best singles of the year by Keisuke Kuwata. "Super Special" was chosen as the ending theme for the Japanese broadcast of the American crime drama series Rizzoli & Isles.[13]

The band's second album Tokyo was released in July 2015.[14] For the album jacket, the band was photographed by Leslie Kee. The track "Final Destination" was used as the ending theme for the second season of Rizzoli & Isles.[15] In June, IDLMs. provided music for the "Nippon Genki Project 2015 Super Energy!!" fashion show produced by Kansai Yamamoto.[15] The band performed their first solo concert at Shibuya WWW on October 25.[16]

In September 2015, the band produced a single titled "The Independent", which was used for Leslie Kee's short film The Independents with fashion designer Yohji Yamamoto.[17]

The band released their third album Fashion in September 2016.[8] Google Play Music in Japan used "Freaky Boy" from the album in their advertisements,[18] and the song "Tonight" was featured as the ending theme for the TBS late-night music television program Count Down TV.[19] They launched their first national tour in October[20] and performed a solo concert at Zepp DiverCity in Tokyo on November 19.[19]

In June 2017, the band released the E.P Summer,[8] which included a dance remix of "Tonight". The limited edition release also contained 11 live videos from the 2016 Japan tour and the final performance at Zepp DiverCity.[21]

In August 2019, their fourth album Future was released, which was the first album under new label Rhythm Zone. The album contained new mixes of "Tonight" and "Fire" created for the release, and the special edition Blu-ray featured a documentary of the band's recent tours and their decision to change labels.[22] Leading up to the album's release, the band performed the new song "Diamond" for the first time at the Join Alive festival in Hokkaido on July 13. The music video for "Diamond" premiered on July 13, with the band members' wardrobe provided by H&M.[23]

IDLMS. released their fifth album Black Humor in August 2021. During the songwriting phase for the album, Yu composed his lyrics with piano to develop the melody simultaneously.[24] A collaboration with UK fashion brand AllSaints was presented to promote the album's launch.[25]

Following Black Humor's release, the band launched a nationwide tour of Japan, performing their largest number of shows in a single tour.[26]

in January 2022, the band released "Paint", which was used for the opening of the One Piece anime.[2] Yu stated an affinity for the series, claiming it was the only manga he has kept reading childhood, and used the teamwork aspect of his own band as inspiration.[27] To prepare for the song's creation, Yu corresponded with One Piece creator Eiichiro Oda to express his thoughts about the series' theme of overcoming adversity.[28]

In July, they performed at the Anime Friends event in São Paulo, Brazil.[7] That same month, their song "Kasaneiro" was used as the theme song for the Japanese television drama Octo: Mind Investigator Akari Shinno.[29]

In February 2023, their songs "Moon Night" and "Wolf Vibes" were used as the opening and ending themes for the TV drama Zenryoku de, Aishite Ii Kana? starring Nanami Sakuraba.[30] On July 2, 2023, they performed at the BubblePop festival in Barcelona, Spain.[31]

Yu writes lyrics in both English and Japanese.[26] The band has noted that the sound of their early recordings was based on international influences, incorporating soul, disco, and pop. The members have cited a range of influences including Katy Perry, Bruno Mars, Kanye West, The Beatles, Oasis, and Peter Gabriel.[32] Beginning with 2021's Black Humor, the band made a conscious decision to focus more on the Japan's domestic J-Pop audience.[27]

The band collaborates equally on song creation, using digital technology to share ideas and build each track remotely when they are not in the studio together.[33] Bass and rhythm for the chorus are created first, and then the melody is added. The band will often reference popular trends in music to decide the overall mood and style of a song.[34]

The band directly supervises the look of their live shows, promotion videos, CD jacket art, and band photos.[35]

In 2021, Shuki and Yu collaborated on the artwork and animated promotion videos for Black Humor.[36]