Archduke Franz Karl Joseph of Austria (17 December 1802 – 8 March 1878) from the House of Habsburg was father of two emperors (Franz Joseph I of Austria and Maximilian I of Mexico) as well as the grandfather of Archduke Franz Ferdinand of Austria, whose assassination sparked the hostilities that led to the outbreak of World War I, and the great-grandfather of the last Habsburg emperor Karl I.

He was born in Vienna, the third son of Emperor Francis II (I) by his second marriage with Princess Maria Theresa from the House of Bourbon, daughter of King Ferdinand I of the Two Sicilies and Maria Carolina of Habsburg-Lorraine. On 4 November 1824 in Vienna he married Princess Sophie of Bavaria from the House of Wittelsbach, a daughter of King Maximilian I Joseph of Bavaria by his second wife Caroline of Baden. The Wittelsbach condoned the unappealing manners of her husband in consideration of the incapability of his elder brother Ferdinand and Sophie's chance to become Austrian Empress.

Franz Karl was an unambitious and generally ineffectual man, although he was together with his uncle Archduke Louis a member of the Geheime Staatskonferenz council, which after the death of Emperor Francis I ruled the Austrian Empire in the stead of his mentally retarded brother Ferdinand from 1835 to 1848. The decisions however were actually made by the Minister of State Prince Klemens Wenzel von Metternich and his rival Count Franz Anton von Kolowrat-Liebsteinsky. His wife Sophie had already given up her ambitions, when she urged Franz Karl to renounce his claims to the throne at the time of his brother's abdication on 2 December 1848, allowing their eldest son Franz Joseph I to take the throne.

Death and burial

Archduke Franz Karl died in Vienna in 1878, six years after the death of his wife. He is buried at the Imperial Crypt at the Capuchin Church. Franz Karl was the last Habsburg whose viscera were entombed at the Ducal Crypt of St. Stephen's Cathedral and whose heart was placed at the Herzgruft of the Augustinian Church according to a centuries-long family rite.