On 26 December 1918 after World War I, Hülsen formed the Freikorps (von) Hülsen, a paramilitary unit which participated in the suppression of the Spartacist League in Berlin. In 1921, Generalleutnant von Hülsen commanded units in the Battle of Annaberg in Upper Silesia. In 1922, he published "Der Kampf um Oberschlesien".