In 1792 Bessières joined Louis XVI's constitutional guard as a private. After serving in Catalonia as a captain, he was chosen to command Napoleon's escort in Italy in 1796. He fought bravely at Aboukir, Egypt, in 1798 and two years later commanded 800 men of the consular guard at the Battle of Marengo (June 14). In 1805, with 9,000 guards, he led the famous charge against the Russian guard cavalry at Austerlitz (December 2).

In Spain Bessières's victory at Medina de Ríoseco (1808) enabled Napoleon's brother Joseph to reach Madrid and establish himself as king of Spain. Commanding the cavalry corps against Austria in 1809, Bessières led charges to cover the retreat in the Battle of Aspern-Essling (May 22) and to gain time at the Battle of Wagram (July 5–6), where he was severely wounded. Yet he was soon sent to end the British Walcheren expedition in Flanders. In 1809 he was created duke of Istria. Sent back to Spain in command of 50,000 men to hold the north, he was unable to bring more than a few of his cavalry to join André Masséna for the Battle of Fuentes de Oñoro (May 3, 1811). In 1812 Bessières led the guard cavalry to Russia and lost them almost without fighting. On the day before the Battle of Lützen (May 2), he was killed in a clash at nearby Rippach while on reconnaissance.