From August 1914 until November 1918, Kubizek served as a reservist in Regiment 2 of the Austro-Hungarian Infantry. In the Carpathian winter campaign of 1915, he was wounded at Eperjes in Hungary (now Prešov in Slovakia) and later evacuated to Budapest in an ambulance train. After months of convalescence, he returned to the front and was attached to a mechanised corps in Vienna. After the war, Kubizek accepted a position as an official in the municipal council of Eferding, Upper Austria and music became his hobby.