[1] It was founded in Bergen in 1995 by Øystein Garnes Brun primarily as a black metal band before later switching to a more melodic and progressive style.

When Garm of Ulver, Head Control System and Arcturus joined the project, it brought the band immediate attention.

Borknagar has toured with various bands including Emperor, Peccatum, In Flames, Morbid Angel and Cradle of Filth.

Borknagar released a lighter album, Origin, which is "an acoustic effort based entirely on the epic and progressive aspect of the band", according to Øystein G. Brun's statement on heavy metal website Blabbermouth.net.

[4] In May 2008, Øystein released another statement announcing Asgeir's departure as the band's drummer, due to "evolving differences in musical ideas and visions [...] The split happens in friendly manner and with mutual respect for the decision that he has made.

[7] In early June 2010, Jan Erik Tiwaz left the bass guitarist position of Borknagar due to "general disagreements",[8] and ICS Vortex replaced him and Vintersorg on the upcoming tour.

[12] Drummer Dave Kinkade announced on his official Facebook page on 25 October 2011 that he had "mutually parted ways with Borknagar" and that he'll "be focusing 100% on Soulfly now".

[15] In early 2019, it was reported that long-time vocalist Vintersorg has parted ways with the band due to conflicting issues with his work and family, as well as the after effects of his 2014 injuries.