He is principally known for his poetry which served to inspire the Norwegian resistance movement during the German occupation of Norway during World War II.
He was an avid opponent of Nazism and in 1936 he wrote the poem "Du må ikke sove" which was printed in the journal Samtiden.
[5] During the German occupation of Norway from 1940 in World War II, he wrote to inspire the Norwegian resistance movement.
He wrote a series of poems which were clandestinely distributed, leading to the arrest of both him and his future wife Margrete Aamot Øverland in 1941.
[citation needed] Øverland played an important role in the Norwegian language struggle in the post-war era.
In addition, Øverland adhered to the traditionalist style of writing, criticising modernist poetry on several occasions.
His speech Tungetale fra parnasset, published in Arbeiderbladet in 1954, initiated the so-called Glossolalia debate.