Early in the war he commanded the militia defending 200 miles of the New York--Canadian border. His successful defense of the Lake Ontario naval base at Sackets Harbor in 1813 was rewarded with a regular army commission as brigadier general. He won more battles against British regular troops than any general in American history, and he was respected by his superiors, his subordinates, and the enemy. In 1821 Brown became commanding general of the army and advised secretaries of war and presidents on military policy.
Brown helped create a professional army. As division commander, and later as commanding general, he was instrumental in establishing the staff and command structure that was operational until the 20th century.