Born in Caulaincourt, Aisne in the French region of Picardy, he began service in the army at the age of 15, serving as an aide to his father.
Caulaincourt, Aisne, a commune of the Aisne département, in France
In 1804 Caulaincourt was appointed aide-de-camp to Louis Bonaparte, with the rank of chef de brigade (colonel) of a dragoon brigade.