The band was formed in 1997 by original members Gunnar Örn Tynes and Örvar Þóreyjarson Smárason, who were joined by twin sisters Gyða and Kristín Anna Valtýsdóttir.

[3] The new collective of musicians recorded their fourth album during 2006; Go Go Smear the Poison Ivy was released on 24 September 2007.

Múm toured the East Coast of the US with German musician Volker "Hauschka" Bertelmann In November 2007.

[9] Múm released their sixth album Smilewound in September, 2013 on CD, vinyl and digital download.

[11] In 2019, Morr Music celebrated the 20th anniversary of múm's debut album, Yesterday Was Dramatic – Today Is OK, by rereleasing it.