Karl von Normann-Ehrenfels was one of the sons of the jurist Philipp Christian von Normann-Ehrenfels, who served as the Kingdom of Württemberg's chief minister in 1806–1812. In 1799 he joined an Austrian cuirassier regiment. He quickly gained a commission as an officer and served alongside the Austrians until the Peace of Luneville. With the help of his father, he then switched to the Württemberg military, rising to the rank of lieutenant colonel and commander of the Chevauxleger regiment of the royal guard by 1810. In 1812, he led his regiment in the French invasion of Russia. In 1813, as a major general, he organized and led a cavalry brigade, initially alongside the French, but on 18 October he went over to the Coalition forces, even though Württemberg continued to stand by its alliance with Napoleon. This action caused King Frederick I of Württemberg to prohibit Normann from returning to Württemberg; only after the King's death, in March 1817, was he able to secure his return to his homeland, although he was still prohibited from entering the capital, Stuttgart.