In 1816, Nugent was given the title of prince by Pope Pius VII. In 1817, he entered the service of King Ferdinand I of the Two Sicilies. He married Countess Giovannina Riario-Sforza who owned property in the small town of Montepeloso (Irsina), in Basilicata. After the outbreak of the Carbonari rebellion in 1820, he returned to serve in the Austrian Army. In 1848, he led an Army Corps under Joseph Radetzky von Radetz against the Piedmontese, in the course of the First Italian War of Independence, and also against the Hungarian Revolution of 1848. He received the title of Field Marshal in 1849.