At an early age, Carson left home to become a trapper in the West. His experience as a frontiersman led to him becoming John C. Fremont's guide in the American West. In the 1846-48 Mexican-American War, Carson fought in California. He eventually settled in New Mexico to become a rancher. He helped organize the New Mexico volunteer Civil War infantry. Although he had no stomach for it, he obeyed U.S. Army orders and fought the Navajo natives.