French statesman and man of letters who served twice as head of the government during the early crucial years of the Third French Republic but failed to prepare the way for the return of a king.

After a brief diplomatic career at Madrid and Rome, Broglie withdrew from public life at the Revolution of 1848. He had already published a translation of the religious system of Leibniz (1846). He contributed to the Revue des Deux Mondes and to the Orleanist and clerical organ Le Correspondant. He was elected to the Académie Française in 1862, while his work L'Église et l'empire romain au IV^e siècle, 6 vol. (1856–66), was still incomplete.

In February 1871 the duc de Broglie was elected to the National Assembly as deputy for Eure. A few days later he was appointed ambassador to London. In March 1872, because of heavy criticism of his negotiations of trade and commercial treaties between Great Britain and France, he resigned his foreign post and took his seat in the National Assembly, where he became a leading spirit of the conservative campaign against Adolphe Thiers, then president of the republic.

On the replacement of Thiers by the conservative Marshal Mac-Mahon, the Duc became president of the council, or premier, and minister for foreign affairs (May 1873) and later of the interior (November 26). His ministry was marked by an extreme conservatism that provoked the bitter hatred of republicans. He also alienated the Legitimists by his friendly relations with the Bonapartists and the Bonapartists by an attempt to effect a compromise between the rival claimants to the monarchy. The Cabinet fell on May 18, 1874.

Three years later (May 16, 1877) Broglie was entrusted by Mac-Mahon with the formation of a new Cabinet, but this proved unable to earn a vote of confidence from the new republican majority in the Chamber. Forced to resign (November 20), he was not reelected in 1885 and abandoned politics for historical work. His Mémoires, 2 vol., were published in 1938–41.