Van Ostaijen worked as a clerk for the Antwerp municipality, whilst writing poetry for local newspapers and magazines. His first series Music-Hall were published in 1916. His initial work was influenced by German Expressionism. In 1918 he moved to Berlin where he published the Dadaist poem Bezette Stad (The Occupied City), with the collaboration of Oscar Jespers. Back in the Netherlands he developed his own style and poetic system. He also wrote essays and prose and was the first translator of Franz Kafka.