In 1851 von Prittwitz joined the Guard Artillery in Berlin, became Second Lieutenant in 1853 and First Lieutenant in 1861. In the Second Schleswig War against Denmark he was assigned to General Helmuth von Moltke the Elder, Chief of Staff of the Prussian Army. Here he participated in Wyk auf Föhr in the capture of Otto Christian Hammer and on 29 June 1864 took part in the crossing of the sound to the isle of Als.