In 1755 Carver joined the Massachusetts colonial militia at the start of the French and Indian War. In 1757, Carver, a friend of Robert Rogers, enlisted with Burke's Rangers. Burke's Rangers would in 1758 become a part of Rogers' Rangers. During the war he studied surveying and mapping techniques. He was successful in the military and eventually became captain of a Massachusetts regiment in 1761. Two years later he quit the army with a determination to explore the new territories acquired by the British as a result of the war.