Born at the Hôtel de Soubise[1] in Paris to the daughter of Gaston d'Orléans and the head of the Princely House of Guise, Francis Joseph would be their only child.

He was a first cousin of the last Medici Grand Duke of Tuscany Gian Gastone de' Medici; he was also of second cousin of Louis XIV and nephew of the famous La Grande Mademoiselle.

He was also a double descendant of Catherine de' Medici and her husband Henry II.

At the death of his maternal grandmother Marguerite of Lorraine in 1672 Francis Joseph and his mother moved into the Luxembourg Palace in Paris.

Still unable to walk unaided at age four, he was dropped by his nurse and died from a head injury in 1675.