During the July Monarchy, Regnaud de Saint-Jean d'Angély served as a colonel in the expedition to Belgium. He was promoted to "général de brigade" in 1841 and to "général de division" in 1849. In 1848, he was elected deputy and sat on the right. In 1851, he served for a fortnight as minister of war. In 1852, he backed Louis-Napoléon Bonaparte and, as a reward, he was made a senator for life. Under the Second Empire, he went through the Crimean and Italian campaigns, and ultimately was created Marshal of France in 1859 for bravery at the Battle of Magenta.