The group's name was originally an acronym based on the first letter of each member's family name: Kazuya Kamenashi, Jin Akanishi, Junnosuke Taguchi, Koki Tanaka, Tatsuya Ueda, and Yuichi Nakamaru.
In 2001, eight members were chosen to become a temporary dancing unit in order to support Koichi Domoto in the NHK music program, Pop Jam.
[11] In March 2006, KAT-TUN became the first group to hold their own performances in Japan's most popular stadium, Tokyo Dome, before debuting.
On November 21, they simultaneously released their fifth single, "Keep the Faith", as the theme song to members Akanishi and Taguchi's drama, Yukan Club, and the DVD to their Tokyo Dome Live of KAT-TUN "Real Face" concert.
[16] KAT-TUN released 'Lips', the theme song to Kamenashi's drama based on the manga One Pound Gospel, as their sixth single on February 6.
This marked a historic event in the Dome's history, as KAT-TUN became the first Japanese artist to hold four consecutive days at the stadium since it opened in 1988.
On February 10, KAT-TUN released their first single since March 2009, which was used for Kamenashi's live-action drama adaptation of Tomoko Hayakawa's manga series Yamato Nadeshiko Shichi Henge, which premiered January 15 on TBS.
[25] Due to the political unrest in Thailand, Johnny & Associates announced on May 15 that KAT-TUN's concert in Bangkok would be indefinitely postponed.
[26] KAT-TUN released their first 2010 album, No More Pain, on June 16 in two versions: a limited and regular edition that both include solo songs by each member.
KAT-TUN will become the fourth Johnny group to be able to conquer the 5 big domes in Japan after SMAP, KinKi Kids and Arashi.
[46] It was announced in mid-June that members Kazuya Kamenashi, Koki Tanaka and Yuichi Nakamaru would star in this year's Dream Boy musicals as the leads, shows will commence from September 3 to 25.
[49] On September 30, 2011, KAT-TUN announced their 17th single "Birth" as the soundtrack to Kamenashi Kazuya's drama "Youkai Ningen Bem" would have been released on November 30.
[51] Music Station presented on Jan 13 with a special report for the 'Most Powerful Group BEST 20' which listed the Top 20 most powerful groups of all time in terms of physical single and album sales, KAT-TUN was listed at number 16 with their five-year debut, 17 singles and 5 albums, together they have sold over 8,450,000 records.
[citation needed] On June 27, KAT-TUN released its 18th single To The Limit, which was used as a tie-up song for Suzuki Solio Bandit CM.
On June 29 Music Station reported that KAT-TUN ranked as No.10 best-selling Heisei era's idol with the total sales of 6,661,293 copies from 17 singles.
[59] In October 2013, Koki Tanaka was removed from the band and the talent agency for having violated his contract, leaving KAT-TUN as a four-man ensemble.
The title track "Kusabi" was used as the theme song for the drama Henshin Interviewer no Yūutsu starring KAT-TUN member Yuichi Nakamaru and actress Fumino Kimura, while "Gimme Luv" was used in a Suzuki Solio Bandit television commercial.
[63][64][65] On November 24, 2015, before their performance at Best Artist, Junnosuke Taguchi surprised the audience by announcing that he had decided to quit not only KAT-TUN but also from Johnny's Entertainment and that he would retire from the industry by Spring the following year.
[66][67] KAT-TUN released two more singles as a four-member group—"Tragedy" on February 10, 2016, followed by "Unlock" on March 2, 2016, both of which had reached number 1 in Oricon chart in their first week.
[70] They also announced that the group activities of KAT-TUN will be on a temporary, indefinite hiatus (or so-called "recharging period") starting on May 1, 2016, as each member focused more on their solo projects and works.
On January 1, 2018, on the annual Johnny's Countdown, a big surprise had been announced and that KAT-TUN had finally resumed their group activities.
[81] Their live tour was later released through DVD and Blu-ray on November 24, which feature footage from the group's concert on May 29 at Pia Arena MM.
[82] In February 2022, KAT-TUN announced the release of their digital single "Crystal Moment", as the theme song for NTV's coverage of the Beijing 2022 Winter Olympics, the rap lyrics were written by Arashi's Sho Sakurai.
Former members Jin Akanishi, Koki Tanaka and Junnosuke Taguchi hosted KAT-TUN Style together from April 2006 until March 2012.
Kamenashi and fellow KAT-TUN member Koki Tanaka paired up to play the lead roles for the shows held in 2007 and 2008.
KAT-TUN was the first Japanese artist to perform for four days in a row at Tokyo Dome during their Queen of Pirates tour.
KAT-TUN regularly appeared in TV commercials to endorse for NTT docomo, SKY PerfecTV!, Rohto and Lotte from 2005 to 2009.
Since 2010, member Kazuya Kamenashi endorses Panasonic's Lamdash shaver and DOLTZ electric toothbrush, and AOKI 3D slim suits.
Since early 2011, the group together has endorsed Suzuki's 'SOLIO' car, and has sung commercial theme songs for Sofina and Wing products.
On August 26–27, 2006 KAT-TUN members were the main personality supporters for the NTV telethon 24 Hour Television: Love Saves the Earth charity program.