Hølmebakk's début in literature came in 1950 with the novel "Don't Talk About the Fall" (Ikke snakk om høsten).
As an author he was a realist, who wrote of existential questions with force and skillfully explored social backgrounds.
“The Terrible Winter” (Fimbulvinteren) (1964) about the German military scorched earth policy during the Liberation of Finnmark by Soviet and Norwegian forces at the end of the Second World War became the film “Burnt Earth” (Brent jord) in 1969, starring Knut Andersen.
Hølmebakk was active in the popular movement against atomic weapons in Norway and one of the initiators of the Sosialistisk Folkeparti.
In 1961 he wrote his then famous article ‘’Brønnpisserne’’ about the suspicious activities and persecutions of communists and other radicals.