Gudin was given the command of the 3rd Division in the Grande Armée and fought in the wars of the Third Coalition and Fourth Coalition between 1805 and 1807. His 3rd Division of the III Corps was the first major formation into action at the battle of Auerstädt and it bore the main brunt of the fighting. It suffered 40 percent casualties, one of whom was Gudin, who was seriously wounded. He participated in forcing the town of Custrin to capitulate and then playing an important part at the battles of Pultusk and Eylau. A count of the First French Empire in 1808, he was named governor of the castle of Fontainebleau the following year. He then took part in several battles of the War of the Fifth Coalition: Thann, Landshut, Eckmühl, the taking of Ratisbon. He was wounded at the great battle of Wagram. In 1812 he was given the command of a division of the second Grande Armée. He was struck by a cannonball during the battle of Valutino, fighting against Russian troops near Smolensk in Russia. His leg was amputated but he developed gangrene and died three days after the battle. However, his heart was taken out to be buried in a chapel in the Père Lachaise Cemetery, Paris.