Having completed a law degree at the universities of Vienna and Prague, Franz (born 1853, died 1938) initially pursued a military career before taking up diplomatic office. From 1879–1882 he was provisional attaché at the Austrian-Hungarian legation in Brussels. In the years that followed he supported his brother in the administration of his estate, and often represented and advised him on various issues.

Between 1894 and 1898 Franz was Imperial Ambassador in St. Petersburg. From this role arose initiatives to consolidate scientific relations between Austria and Russia. He acquired, for instance, the large library of the Russian historian Bilbasov and in 1907 established chair and seminar in eastern European history at the University of Vienna.

In 1911 Prince Franz I founded the Central Commission for the Conservation of Monuments. In keeping with his interest in history, he headed several specialist associations and was involved in the establishment of several historical publication series.

In 1914 he became an honorary member of the Academy of Science in Vienna. In 1917 he became an hereditary member of the upper house. Distinguished with numerous domestic and international awards, the prince handed over the regency of the House to his young relative Franz Josef II shortly before his death in 1938.