On 7 July 1756 he was promoted to major and, in 1758, commander of the regiment, which now called "Thadden zu Fuss". In the Seven Years' War, he fought in the Battle of Gross-Jägersdorf and Battle of Zorndorf (1758). In 1759 he fought mainly in Pomerania and Mecklenburg, 1761 in Saxony and Silesia, and, in 1762, in Silesia. On 21 July he led two partial regiments in storming the Leutmannsdorf Hill during the Battle of Burkersdorf and was rewarded for this courage with the Order Pour le Mérite.