As the original bassist of Norwegian black metal pioneers Emperor, Mortiis was credited with stimulating the group's interest in blending furiously chaotic black metal with haunting synthesizer melodies often based loosely on Norwegian folk, thus laying the groundwork for a sound that would dominate underground metal over the next decade. However, for all his impact, Mortiis was only with the group for a very short time; he played on their 1992 Wrath of the Tyrant demo, a split release with Enslaved titled Hordanes Land, and a 7" single, "As the Shadows Rise," but never an official full-length album. Mortiis left Emperor rather abruptly in 1993 to pursue a solo career; still only 18 years old, he moved to Halmstad, Sweden, where he formed his own Dark Dungeon label. His 1993 solo debut, Født Til Å Herske, was a surprising departure from Emperor's relentless intensity, and in fact from guitar-oriented music altogether; instead, Mortiis worked primarily with electronic instruments, creating a sorrowful, sinister ambience with more than a hint of goth rock. Ånden Som Gjorde Opprör followed in 1994, as did the first of several side projects: a more industrial-tinged group called Vond, who issued an album titled Selvmord (later released in the U.S. as Slipp Sorgen Los). 1995 brought another new Mortiis album (Keiser av en Dimensjon Ukjent, or Emperor of a Dimension Unknown) and another side project, this one called Fata Morgana, who issued a self-titled debut. In 1996, Mortiis recorded a limited-edition series of five 12" EPs, whose material was subsequently collected as Crypt of the Wizard; 1997 brought yet another side project, the somewhat lighter Cinticele Diavolui.

No new Mortiis recordings appeared for a while, mostly due to negotiations with record companies. In 1999, Mortiis put an end to his side projects and signed to Earache, who promptly released his new project, the ambitious The Stargate, which featured heavy female vocals courtesy of Cradle of Filth's Sarah Jezebel Deva. Earache also reissued Født Til Å Herske and Crypt of the Wizard a short time later, and the proper international distribution of those records elevated Mortiis' profile and began to build a cult following for his music. 2001's The Smell of Rain signaled a sonic departure for Mortiis, who added in elements of electropop and took on lead vocals for the first time. 2004's The Grudge also tinkered with the recipe by introducing a heavy industrial rock emphasis to the proceedings. The album spawned a collection of remixes, Some Kind of Heroin, which dropped in 2007, and in 2010 Mortiis issued Perfectly Defect as a free, internet only download. Mortiis spent the ensuing years on hiatus, reemerging in early 2016 with the all new Great Deceiver. ~ Steve Huey