He never succeeded to the crown because on 29 November 1918, when Württemberg"s monarchy was abolished in the collapse of the German Empire following World War I, his kinsman of the senior branch of the dynasty, Wilhelm II, was still king (and lived, after his abdication, until 2 October 1921). In 1865 Philip of Württemberg married Archduchess Marie-Thérèse of Teschen (1845–1927) (daughter of Archduke Albert, Duke of Teschen and Princess Hildegard of Bavaria). Philip of Württemberg belonged to the fifth branch (called the "Ducal branch") of the House of Württemberg, descended from the seventh son of Frederick II Eugene, Duke of Württemberg.
On the extinction of the eldest branch in 1921, the Catholic ducal line remained the only dynastic branch of the formerly reigning family.
The House of Württemberg"s two morganatic branches - that of the Dukes of Teck (extinct in the male line in 1981), and of the Dukes of Urach - were genealogically senior to the Ducal branch, but had been ineligible to succeed to the throne. Philip is the direct ancestor of the current claimant to the Kingdom of Württemberg: Carl, Duke of Württemberg.