Friedrich Wilhelm married Princess Margarita of Leiningen (1932–1996) on 3 February 1951. She was a child of Karl, 6th Prince of Leiningen, and his wife, Grand Duchess Maria Kirillovna of Russia. They had three children: Karl Friedrich, Prince of Hohenzollern (born 1952), who succeeded Friedrich Wilhelm as head of the House of Hohenzollern;
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.