After service in the eastern Pyrenees, northwestern France, and Italy, he rose to general of division in 1802 and distinguished himself during the Peninsular War (1809–12). Having crushed the Bordeaux royalists during the Hundred Days, he was made a peer of France by Napoleon (1815) but had to flee to the United States in 1816 to escape prosecution under the Restoration. Returning to France under the 1820 amnesty, he was elected deputy for Ariège in 1827. After the July Revolution of 1830 he temporarily replaced Marshal Bourmont in command in Algeria. On his recall he was elected deputy for Ardennes (October 1830) and made marshal of France (February 1831).

Convinced of Algeria's possibilities, he proposed that settlers be brought there from all countries, that cotton be grown there, and that the Mitidja Plain be drained and protected by a network of blockhouses. Presenting himself as the only man capable of establishing and extending the French colony, he secured appointment as governor (1835). The French Cabinet, however, would not condone his aggressive policy. When he precipitately attacked Constantine (Algeria) and was defeated (1836), he was recalled to Paris and relieved of his post.