At this age, he was also inducted into the Upper House of Parliament. He served in the Austrian army until the fall of the Habsburg Empire, after which he served with great distinction in the Polish army. The marriage was acceptable through morganatic.
Their children, among them Count Leo Stefan of Habsburg (b 1928), were granted the title of Count of Habsburg.
He died of tuberculosis on the 28 April 1939 at his estate in Bestwina, in southern Poland. He was buried in the local cemetery in Bestwina, a countryside plot belonging to his family.
Bestwina was also the location of the palace where he and his family moved to in 1933, after the death of his father, Karl Stefan.