Of the second generation of the family the most important was Louis Bonaparte's son, Louis Napoleon, who became emperor as Napoleon III (see also separate article for Napoleon II, son of Napoleon I and Marie Louise).
Other members of the family also became prominent. Charles Lucien Jules Laurent Bonaparte, 1803–57, prince of Canino, son of Lucien, lived in the United States from 1824 to 1833 and was important as a naturalist, particularly as author of American Ornithology (4 vol., 1825–33, in English). He took part in the Roman insurrection of 1848. Pierre Napoléon Bonaparte, 1815–81, another son of Lucien, after an adventurous career as soldier of fortune, became a French politician. Although a Republican, he accepted the empire of Napoleon III. In 1870 he killed the journalist Victor Noir in the heat of a quarrel but was acquitted of murder.
Pierre was notoriously immoral, as was his cousin Napoléon Joseph Charles Paul Bonaparte, 1822–91, commonly called Prince Napoleon or, more familiarly, Plon-Plon. The son of Jérôme and Catherine of Württemberg, he was named as successor to his cousin Napoleon III, in case the emperor should die childless. He was, however, a liberal and on occasion opposed the emperor's measures. His marriage (1859) to Princess Clotilde, the daughter of King Victor Emmanuel II, was a move in Napoleon III's Italian policy.
Prince Napoleon became a pretender to the throne after the death of the only son of Napoleon III, Napoléon Eugène Louis Jean Joseph Bonaparte, 1856–79, the Prince Imperial, who was killed while fighting the Zulus as a member of the British army. Napoléon Victor Jérôme Frédéric Bonaparte (Victor Bonaparte), 1862–1926, inherited the claims of Prince Napoleon, his father.
The daughter of Jérôme and Catherine of Württemberg, the princess Mathilde Bonaparte, 1820–1904, was prominent during and after the second empire as hostess to men of arts and letters. Marie Bonaparte, 1882–1962, granddaughter of Pierre Napoléon, was a disciple and friend of Sigmund Freud. She helped Freud escape from Vienna after the German invasion in 1938.
By his American wife, Elizabeth Patterson, Jérôme Bonaparte had a son, Jerome Napoleon Bonaparte, 1805–70, from whom the American line of the Bonaparte family is descended. The most prominent of this line was Charles Joseph Bonaparte.