Bjørnson and Kjellson had been playing in a death metal band called Phobia, but like many in the burgeoning extreme metal movement, they were looking for new sources of inspiration and expression. Though Enslaved began as a prototypical Norwegian black metal band, they always incorporated song structures unusual for the genre, with several of their early songs expanding past the ten-minute mark. As such, the band has rejected the black metal genre label and prefers the term 'extreme metal'. The album Eld (1997) is often considered to be the beginning of the band's shift towards progressive metal. The band's shift toward progressive viking metal was rendered complete with Mardraum (2000), which contained several multi-part epics such as "Større enn tid - Tyngre enn natt" and "Entrance - Escape"; from that point onward, the band's influence from progressive rock became stronger on each successive record, with several tracks (most prominently, "As Fire Swept Clean the Earth" from Below the Lights) even using mellotron. Mardraum, Monumension (2001), and Below the Lights (2003) can be regarded as having somewhat similar styles, although there is a clear progression of sound between the albums regardless; however, Isa (2004) and Ruun (2006) show a marked departure from previous sounds, most notably, with inclusion of sharp dynamic shifts.

Although the band has used mainly English lyrics since Monumension, their albums before that were mostly recorded in Norwegian except on their first full-length album, where three songs had Icelandic lyrics, while the lyrics on Heimdallr was an Old Norse excerpt from Gylfaginning by Snorri Sturluson. Most of their lyrics relate to Norse mythology.

Enslaved released the album Vertebrae in September 2008. On this particular album, many of their techniques, particularly harmonies, have been compared to Pink Floyd. After touring Europe extensively, Enslaved embarked on a North American tour with the progressive death metal band Opeth in May 2009. Enslaved released their eleventh studio album, Axioma Ethica Odini, on September 27, 2010 in Europe and the following day in North America.