Archduke Ferdinand Karl Joseph of Austria-Este was the third son of Archduke Ferdinand of Austria-Este and of his wife Princess Maria Beatrice Ricciarda d'Este, last member and heiress of the House of Este. For much of the Napoleonic Wars he was in command of the Austrian army.

Archduke Ferdinand Karl of Austria-Este was a son of Holy Roman Emperor Franz I and Maria Theresa of Austria. He was the founder of the House of Austria-Este and Governor of the Duchy of Milan between 1765 and 1796. He was also designated as the heir to the Duchy of Modena and Reggio, but he never reigned, owing to the Napoleonic Wars.