Witzleben became a squire to King Frederick William II in 1793, and then an Ensign in the personal body guard in 1799. He became a Second Lieutenant in 1802, and was captured in the Battle of Jena in 1806, but was exchanged in August 1807. His work Ideas on the Reorganisation of the Light Infantry, caught the attention of Gerhard von Scharnhorst, so that he was transferred in December 1808 to the newly formed Garde-Jäger-Bataillon as a Stabskapitän. In early 1812 he was promoted to Major and fought on 2 May 1813 in the Battle of Lützen. During the war in France he was promoted to Lieutenant Colonel. In spring 1815 he joined the general staff of the army of Field Marshal Blücher and was then made a Colonel.
Having been made a Lieutenant General in 1821, he was appointed the successor of Minister of War Karl Georg Albrecht Ernst von Hake upon his resignation in 1833. He worked to integrate the standing army and the Landwehr. He also managed the introduction of the needle gun, and revised the military criminal code.
Wilhelm Dorow: Job von Witzleben, königl. Preuß. Kriegsminister. Mittheilungen desselben und seiner Freunde zur Beurteilung preuß. Zustände und wichtiger Zeitfragen. Tauchnitz, Leipzig 1842 (Digitalisat)