His father was Philippe Emanuel, 2nd Prince of Hornes, and his mother was Princess Marie Anne Antoinette of Ligne.
He first married Lady Marie Thérèse Charlotte Bruce (1697–1736), daughter of Thomas Bruce, 2nd Earl of Ailesbury, an English nobleman who lived in exile in Brussels for much of his life, and his second wife Charlotte d'Argenteau, comtesse d'Esneux.
Their children were: 1) Marie-Thérèse-Josepha de Hornes (19 October 1725 – 19 June 1783):married Prince Philip Joseph of Salm-Kyrburg.
They had 10 children: 2) Elisabeth-Philippine-Claude de Hornes (1733–1826):married Prince Gustav Adolf of Stolberg-Gedern.
They had four daughters: Following his first wife's death, he was married to Princess Henriette Thérèse Norbertine of Salm-Kyrburg (1711–1751) and then, after her death, to Princess Marie Albertine de Gavre (1735–1797), daughter of Charles I Alexandre, 1st Prince de Gavre.