The idea of Gallhammer originated in 2002 by Vivian, who wanted to form a band based on the dark and morbid atmospheres of Hellhammer. The other members joined the following year and Gallhammer was born in February 2003, before each member had even learned to play their instruments. This was because they had all been vocalists in their previous bands, but their influences and tastes varied greatly.

Vivian was a vocalist in a Grind Core band and had also played saxophone in a Noise group. Risa was a vocalist in an Avant-garde project, and Mika sang in a rock band. By March 2003, Gallhammer had already recorded a demo tape which was limited to just 30 copies and was given away for free at their first gig at Koiwa Death Fest Vol.2. At early gigs their set also included covers of Hellhammer and Amebix tracks, the main influences of the band. Only a few months later in July, the demo CD 'Gallhammer' was recorded and released Vivian's vision of Gallhammer had been realised in that it should sound like 'Dark, Morbid and raw sensibility' with the emphasis on raw feelings. Gallhammer is the essence of mental violence, with lyrical themes covering topics such as 'despair and hopelessness, emptiness, obsession with life, hatred, observations of negative feelings'.

By April the following year a new demo CD "ENDLESS NAUSEOUS DAYS" was released and the band started to plan their debut full-length CD, which would feature reworked and re-recorded songs from their earlier demos and compilation appearances. The band kept playing live around Tokyo such as the Gallhammer headline gig entitled "Aloof and Proud Silence vol.1" at Shinjuku D.O.M in August 2004 and also "Aloof and Proud Silence vol.2" at Nishiogikubo WATTS later the same year, in the process gaining plenty of experience and a devoted following wherever they played. On November 11th 2004 their debut album was unleashed by 'Hello From The Gutter' Records, entitled 'Gloomy Lights', this 8 track album was a dedication to their influences but also created a new, unique and dark sickly sounding atmosphere of their own.

Gallhammer signed to Peaceville Records in 2006 after the label was stunned by the energy and presence of the band’s live footage, and in early 2007 Peaceville released ‘The Dawn of…’, a CD collection of demo recordings which also included a DVD of live shows in Japan, which brought this fantastic new band to the music world’s attention, with Gallhammer gaining much acclaim for their attitude and songs, The Guardian, UK, even giving them the honour of ‘band of the day’, plus numerous outstanding reviews, all in anticipation of the debut Peaceville studio release from Gallhammer ‘ILL INNOCENCE’, due September 2007, at the same time as the band embark upon their debut European tour. ‘Ill Innocence’ was recorded & mixed by Makota Fujishima of Weird Truth Productions in during late 2006/early 2007 and the album was mastered in Oslo by Nocturno Culto of black metal legends, Darkthrone.

Although Gallhammer had been known primarily as a black metal/punk act, the album was impressively diverse, showing their implementation of many influences and moods from both metal and non-metal genres. The themes were based around isolation, oppression, a world without colour, with Vivian describing the imagery like “Delirium - as being in a midday nightmare under the scorching sunshine”; all wrapped in a poetic disparity. ‘Ill Innocence’ also featured recordings of the tracks ‘Speed of Blood’ & ‘At the Onset of the Age of Despair’ as previewed in demo form on ‘The Dawn of…'
The album was met with great critical acclaim, particularly in the UK, with the band even given the honour of coverstars in metal publications Zero Tolerance & Terrorizer magazine, and ‘Ill Innocence’ was further backed up by Gallhammer’s first European tour, alongside Norwegian band Skitliv, the project created by ex-Mayhem vocalist, Maniac