Thorr's Hammer was formed in Ballard, Washington by Greg Anderson and Stephen O'Malley during winter 1994-1995. Soon after, Runhild Gammelsæter, then 17-year-old Norwegian exchange student, joined the band as vocalist/lyricist. The band reached its final form when Jamie Sykes and James Hale joined. The band was active only for six weeks during which it played two gigs and recorded a demo and an EP entitled Dommedagsnatt. The band disbanded after Runhild's return to Oslo, Norway. Burning Witch was formed from the ashes of Thorr's Hammer and Runhild has currently teamed up with James Plotkin (Khanate) to form Khlyst.

Thorr's Hammer reunited in 2009 to play at the Supersonic Festival in Birmingham, England. In an interview with Rock-A-Rolla magazine, Runhild Gammelsæter said the band "might make some new music" in the future.