Friedrich Karl was born at the Royal Palace in Berlin on 20 March 1828, as the only son of Prince Charles of Prussia, the brother of future German emperor William I. From 1842 to 1846, Frederick Charles was under the military tutelage of then Major Albrecht von Roon. In 1845, the Prince joined the army and was sent to an infantry company.
Biography. He joined the army in 1934 (infantry regiment 8 in Frankfurt/Oder) and participated in the Invasion of Poland in 1939. One year later he was dismissed from the army by Hitler's Prinzenerlaß, following the death of his elder brother Prince Wilhelm of Prussia, who was wounded in France on 23 May 1940 and died in a Field hospital in Belgium three days later.