Galneryus was formed in early 2001 by guitarist Syu (formerly from Valkyr, Animetal, Aushvitz, and Masaki Project) along with vocalist Yama-B, frontman of AxBites, Rekion, River End and solo artist of Gunbridge. Both veterans of the Japanese metal scene they formed Galneryus with the intention to "express both of their musical tastes/ideas" and so they started looking for additional members to complete the band. They recruited A ..boards (who had previously played with Syu on Valkyr), Shôgo Himuro on Bass, and Toshihiro Yui (formerly of Cemetery, Honey Quest) on Drums.
In October 2001, the band released a 2-track demo titled United Flag. The demo was self-produced and released independently. This EP started gaining the attention of both fans and independent Japanese record labels as well.
After playing with other Japanese metal bands like Fairy Mirror, Mephistopheles, Galactica Phantom, Mastermind, and Concerto Moon, Galneryus went back to the studio to record a second EP titled Rebel Flag which was released through the independent label Iron Shock in August 2002. The EP again used support musicians to fill the band slots, with Shôgo Himuro again in bass, Toshihiro Yui again on drums, and Yoshinori Kataoka ..boards (replacing A).
After this EP, the band started receiving several record deals and started touring more. In 2003, they were invited to play the 'Melodic Metal Festival' in Japan which featured Swedish power metal band Dragonland, as well as Australia's Dungeon. As a result, Dragonland invited Galneryus to play with them the next time they toured Japan.
Galneryus was also invited to perform on two metal compilation cover albums with other bands such as Masaki Project, Saber Tiger, and Mephistopheles. Galneryus performed the song "Black Diamond" (originally from Finnish power metal band Stratovarius) on the compilation album Stand Proud! III and performed the song "Soldier of Fortune" from Japanese heavy metal band Loudness on the compilation album Japanese Heavy Metal Tribute Tamashii II. For these songs, the band used supporting musicians Toshihiro Yui on drums, Yusuke on bass, and Yuhki ..boards. Both compilation albums were released simultaneously in December of 2002 on the same day through Iron Shock and distributed through Japanese record label VAP.
VAP itself signed Galneryus and the band set to work on writing and recording their full-length album The Flag of Punishment which featured all 5 EP songs re-written and re-recorded and also cover art by famed Final Fantasy artist Yoshitaka Amano. At this time Galneryus ceased using temporary members and recruited permanently Tsui on bass, Yuhki ..boards (formerly of Ark Storm and Marge Litch), and Junichi Satoh on drums. The album was finally released in October 2003.
In March 2005 Galneryus released their second album Advance to the Fall. They released their third full-length album (Beyond the End of Despair...) in July 2006.
After the Live for Rebirth tour, Tsui left Galneryus and Yu-To (Deluhi) was recruited to fill in for bass. The band shortly after released One for All - All for One in 2007.
Recently, Galneryus has debuted on iTunes Music Store making their material widely available in the United States.