On 5 June 1723, at the request of his father, nine-year-old Friedrich von Platen was appointed cornet by King Friedrich Wilhelm I of Prussia; and on 18 August 1729, he became a second lieutenant; on 7 July 1730, he became a first lieutenant. On 11 August 1736, he received his own company in the Cuirassier Regiment "Gessler" No. 4. In the same year, he was accepted into the Johanniterorden in Sonnenburg. At the beginning of the First Silesian War (also called the War of Austrian Succession), he was "Rittmeister", a captain of cavalry. His regiment was late for the Battle of Mollwitz but, in 1742, his regiment was involved in the thick of action at the Battle of Chotusitz. He was awarded the Pour le Mérite for his part in executing a successful retreat to Camenz. He was later promoted to major. In 1744 he fought in Bohemia and Moravia. On 22 May 1747, he was promoted to lieutenant colonel; in 1752, he was part of the famed Bayreuth Dragoons and, in 1755, second commander in the Dragoon Regiment "Normann", No. 1.