As aide-de-camp to Marshal Jean Lannes in 1805, Quiot participated in the battles of Ulm and Austerlitz, before receiving his own command, that of the 100th Regiment of the Line. In 1806, he was wounded at the Battle of Jena-Auerstedt, the decisive defeat of the Prussian Army. His successful attack on the Prussian left flank earned him the Legion of Honor. When the War of the Fourth Coalition concluded in 1807, he moved to Spain where he served in the Peninsular War. He served in the brutal but successful second siege of Zaragoza in 1808-1809 and was rewarded by being made a peer of the Empire.