The classic line up of Tatsuro on vocals, Miya on guitar, Yukke on bass, and Satochi on drums was solidified in 1999 following the departure of original bassist Hiro.

[14] Their fourth studio album Kuchiki no Tō was released on September 1 and supported by the Sōran Shūkyō fall tour, which ended on October 31 at Hibiya Open Air Concert Hall.

[19] In addition to opening for Guns N' Roses on the Japanese leg of their 2007 World Tour, Mucc gave performances in Shanghai, in Finland at Provinssirock, and in the US at JRock Revolution Festival.

[20][21][22] They also performed at the Abstinence's Door #001 event hosted by D'erlanger, and their song "Chain Ring" was used as the ending theme to the Zombie-Loan anime adaptation.

[25] Throughout 2008, Mucc participated in the Taste of Chaos 2008 tour,[26] which initially stopped at forty cities across the United States and Canada from February to May, along with fellow Japanese bands D'espairsRay and the Underneath.

[30] After performing in Sweden at Metaltown Festival in June,[31] their Solid Sphere Tour began with a live in Russia on October 3,[32] before featuring their first shows in Latin America (Chile and Mexico).

[43][44] The single "Akatsuki" was first sold exclusively at those concerts, before later being available as a digital download with all proceeds donated to aid the victims of the 2011 Tōhoku earthquake and tsunami.

[46] They also performed at the V-Rock Festival '11 held at Saitama Super Arena on October 23, before releasing the single "Arcadia" which featured DJ Daishi Dance in November.

[57] The single "Mother" was released on October 31, and was an ending theme of Naruto Shippuden, while its B-side "Negative Dancer" features the audience of their September 13 concert singing the chorus.

[60] The Shangri-La tour took place between December 2012 and March 2013, with a special concert on June 7 that marked the end of Mucc's 15th anniversary celebrations.

[64] After interviews and reviewing resumes on a live broadcast on Niconico on July 26, the winners were selected by Mucc's four primary members themselves and given stage names.

[67][68] Mucc performed at Shibuya-AX for Angelo's Intersection of Dogma event on August 16, and at World Memorial Hall on October 20 for Vamps' Halloween Party 2013.

[76] April's Episode 2 VS consisted of a two-man tour where each of the nine dates included another band; either The Telephones, The Back Horn, Rottengraffty, Fake?, Sebastian X, or Straightener.

[79] Armageddon was Episode 6 and consisted of a two-man tour with a different act at each venue; Alexandros, Kishidan, Granrodeo, Buck-Tick, Sid, D'erlanger, Golden Bomber, Michael, and Geek Sleep Sheep.

[87][88] On December 27, Mucc faced Sid in the main event of Maverick DC's Battle Arena in Budokan, where each band alternated playing songs before joining together for the last two.

[91] Mucc performed at Dappe's Rock in Jōsō on May 1, a concert organized by Toshi-Low of Brahman to help revitalize Ibaraki Prefecture after flooding the previous year.

[94] Mucc released the single "Classic" on September 19, and it was used as the opening theme song of The Seven Deadly Sins: Signs of Holy War.

[114] For February 13's concept album Kowareta Piano to Living Dead, Mucc recruited keyboardist Tooru Yoshida as a limited-time member.

[128] On December 2, 2020, Mucc announced that Satochi, who had been their drummer for 23 years, would be leaving the band in spring 2021 and cease activities as a professional musician.

[130] The final two concerts were postponed again due to the pandemic and took place on October 2 and 3 at The Hirosawa City Hall in the band's home prefecture of Ibaraki.

[136] They held two special 25th anniversary lives on February 6 and 14, 2023, which also marked the first time in about three years that the audience could cheer aloud, as it was previously not allowed due to COVID-19 guidelines.

[140] A grand final to their 25th anniversary tour was held at the Tokyo International Forum Hall A on December 28, where they were joined by special guests Ken and Sakura.

[143] From June 9 to August 4, they will hold the Love Together tour, with all but the first two dates featuring a support act; either Kizu, Nogod, Amai Bōryoku, Vistlip, Chaqla., Mama., Jiluka, Arlequin, Divers Croix, or Dezert.

[144] The February 2024 issue of Rockin'On Japan wrote that, ever since their formation in 1997, they have "maintained their own aesthetic, while pursuing music and rock with intellectual curiosity, creative planning, and bold actions, all without being restrained by the boundaries of genres or scenes.

[146] Miya, the principal songwriter of Mucc's music, said he personally likes bands that are ever-changing and play a wide variety of genres.

[11] According to Ed of Real Sound, Mucc already had a unique musicality by the time of their 1999 demo "Shūka", where they fuse the nu metal of Korn with Shōwa era kayōkyoku.

[151] Miya said prior to Zekū (2003) and Kuchiki no Tō (2004), his lyrics were about past events and "traumas" he experienced, but with those two albums he wrote about present inner feelings within the band.

[152] Despite audiences loving the shows, he seems to regret having done this as he speculated that he drank a lot on those tours so he would not have to face what he was expressing on stage, and stated that there is one song on Kuchiki no Tō that he will no longer play.

[160] Tatsuro said he got the idea after seeing Cocco's April 20, 2001 performance on Music Station, where the barefooted singer abruptly left the studio after finishing her song.

[161] He further explained that this was in Mucc's indie days when they had no money; whenever they were putting together new costumes, the shoes were typically the most expensive part, but as a visual kei band they could not simply wear sneakers.