The next year he fought at the battle of Austerlitz and in 1806 he resumed his duties as aide-de-camp to Louis Bonaparte, who had become King of Holland.

In 1808 Caulaincourt rejoined the French Army and was made général de brigade (brigadier general) and a baron of the Empire, just before being sent to fight in Spain.

Caulaincourt was badly wounded in early 1810 and spent time recovering in France, where he was called back to service in 1812 as part of the second Grande Armée that Napoleon I assembled with the purpose of invading Russia.

[2] Caulaincourt was killed at the Battle of Borodino on September 7, 1812, by a cannonball while leading the French assault of the great redoubt.

Following his death at the Battle of Borodino, Napoleon told his brother, the Grand Ecuyer, Armand de Caulaincourt, the Duke of Vicenza, that his loss was a terrible blow and that he was being groomed for high command.