[3][4] He is the sole founding member and chief ideologist of the black metal band Gorgoroth, formed in 1992, in addition to being the founder and head of Forces of Satan Records.

[4] The first Gorgoroth demo, A Sorcery Written in Blood, was released in 1993, and led the band to acquiring a record deal with French label Embassy Productions.

Joining members of black metal bands such as Ulver, Immortal, Enslaved, and Molested, Infernus participated as bassist on Borknagar's self-titled debut album, released in 1996.

In 1998, Infernus and Gorgoroth-guitarist Tormentor, who had joined the band in 1996, released an album as black metal side project called Desekrator, which also included members of Enslaved and Old Funeral.

[6] On 1 February 2004, Infernus and Gorgoroth performed a live show in Kraków, meant to be released on a video album by Metal Mind Productions.

[12] With the departure of Gaahl and King, Infernus recruited drummer Tomas Asklund of Dissection and bassist Bøddel of Obituary, as well as former-Gorgoroth vocalist Pest and guitarist Tormentor for the recording of their next album.

Infernus is a theistic Satanist and, as the founding member of Gorgoroth, has built the band on his philosophy and religion, proclaiming himself as 'Satan's Minister on Earth.

'[17] He has expressed opposition to the Church of Satan based on commercial frivolity, and when asked about this on a couple of occasions in 2009, he also said that he disagreed with their basic values:[17][18]'Basically, because they reject a theist view upon being.