Wahlöö's career in journalism started in 1947 in Sydsvenskan in Malmö and continued in 1949 at the new "Evening Post", where he was a permanent employee, to 1953. He moved onto freelance work in the 1950s, writing theater reviews and film articles for various newspapers including for the newspapers in Norrköping before moving to Stockholm. By May 1964 Per Wahlöö's journalistic path was said to be complete. Subsequently, he was involved in the New Left journal "Tidsignal (Time Signal)" (1965–1970) where he was part of the editorial board, among others including the writer .