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;
Prince Eitel Friedrich was born on 7 July 1883 as the second son of the then Prince Wilhelm of Prussia, and his first wife, Princess Augusta Victoria of Schleswig-Holstein. He was born in the Marmorpalais of Potsdam in the Province of Brandenburg , where his parents resided until his father acceded to the throne as Emperor Wilhelm II in 1888.