At the outbreak of the Seven Years' War he was a lieutenant. When the Corps was supplemented with two squadrons of Saxon soldiers, he received a command over them. According to Friedrich Adolf Graf von Kalckreuth, Wakenitz personally took Georg Christian, Fürst von Lobkowitz as prisoner in the initial skirmishing of the war. On 1 October 1756, he fought at the Battle of Lobositz; he became "Rittmeister" (captain of cavalry) on 24 February 1757. The Corps subsequently fought at the battles of Prague, Roßbach and Leuthen. The Corps commander, Lieutenant Colonel von Blumenthal, who had been severely wounded in Lobositz, died, and his planned successor had left the army because of disagreements. Thus "Rittmeister" Wakenitz became commander of the "Garde du Corps" from 1758–1760. At the engagement in the Battle of Zorndorf, he was able to turn the Russian flank and was immediately promoted to lieutenant colonel. Among the leaders of the "Garde du Corps", he was unquestionably the most meritorious, and according to the judgment of Friedrich Wilhelm von Seydlitz, he was a man worthy to be placed at the head of the Prussian cavalry, but he must have made enemies; he was told that in Zorndorf he had taken a Russian officer, contrary to orders, into his protection, and the Russian had shot a member of the "Garde du Corps". On 6 May 1760, he was promoted to Colonel and Commander of the Cuirassier Regiment No.5 (Markgraf Friedrich). He went to Berlin, but on the occasion of the Russian-Austrian occupation of the city, he became a prisoner of war on 7 October 1760. He was freed when the new Czar Peter III, withdrew from the war with Prussia. Wakenitz returned to Prussia in 1762, and he requested his leave, which he received on the 11 December 1762.