Gourgaud rose through the ranks of the French imperial army, was wounded a number of times, and apparently saved Napoleon from a pistol wound at the Battle of Brienne (January 1814). After a brief flirtation with royalist forces following Napoleon's abdication in 1814, he rejoined the emperor during his “Hundred Days” and then voluntarily accompanied him into exile at St. Helena. Gourgaud's two-volume Sainte-Hélène; Journal inédit de 1815 à 1818 (1899; The St. Helena Journal of General Baron Gourgaud) remains one of the basic accounts of Napoleon's last years.

Gourgaud returned to France in 1821, reentered the army, and continued to rise in rank. He wrote a number of valuable historical works, including Campagne de dix-huit cent quinze (1818; “The Campaign of 1815”), Napoléon et la grande armée en Russie (1824; Napoleon and the Grand Army in Russia), and Réfutation de la vie de Napoléon par Sir Walter Scott (1827; “Refutation of Sir Walter Scott's Life of Napoleon”). In 1849 Gourgaud, by then a baron and a peer of France, was elected to the Legislative Assembly, where he became an influential supporter of Louis-Napoléon (later Napoleon III).