He bore arms during half a century, made war in the four quarters of the globe, opened and terminated thirty-two campaigns. In his youth he acquired, under the eye of his father, who was an engineer officer, the talent of tracing plans and finishing them with exactness, as well as the preliminary qualifications necessary to form a staff-officer. Admitted by the Prince de Lambesq into his regiment of dragoons, he was taught the skilful management of his horse and his sword—accomplishments so important to a soldier. Attached afterward to the staff of Count Rochambeau, he made his first campaign in America, where he soon began to distinguish himself by his valor, activity and talents. Having at length attained superior rank in the staff-corps formed by Marshal de Segur, he visited the camps of the King of Prussia, and discharged the duties of chief of the staff under the Baron de Bezenval.
During nineteen years, consumed in sixteen campaigns, the history of Marshal Berthier’s life was little else but that of the wars of Napoleon, all the details of which he directed, both in the cabinet and the field. A stranger to the intrigues of politics, he labored with indefatigable activity; seized with promptitude and sagacity upon general views, and gave the necessary orders for attaining them with prudence, perspicuity, and conciseness. Discreet, impenetrable, modest; he was just, exact, and even severe, in everything that regarded the service; but he always set an example of vigilance and zeal in his own person, and knew how to maintain discipline, and to cause his authority to be respected by every rank under his orders.