Gunnar Gunnarsson was born into a poor peasant family on the farm Valþjófsstaður in Northeast Iceland. His mother died In 1897. When he was 18, he went to Denmark. In Askov he attended a folk high school and learned to know Franzisca Jörgensen , whom he married on August 20, 1912. He lived as a writer in Denmark until 1926, when he returned to Iceland back. He bought a farm near Vopnafjörður. In 1939 he moved into the farm Skriðuklaustur near his native village. 10 years later he moved to Reykjavík, where he translated his work in Icelandic. Until then he had published in Danish.
In 1906 he published his first poems. In 1912 the first part of his novel, which eventually would have four parts. These novels brought him fame. He also published plays, but above all novels and stories.
- Advent (1938)
- The allies, (Fóstbrædur, 1921)
- The Deensche woman (Danska frúin, 1916)
- The boy (Drengurinn, 1918)
- The Young Eagle (Örninn ungi, 1919)
- Nach threatens the North (Heidaharmur, 1945)
- Ormarr Ørlygsson (1915)
- The Wolf in the Sanctuary (Vargur í véum, 1920)
- The Wanderer (Gestur eineygdi, 1917)