Carson was born in Madison County, Kentucky, but spent his childhood in Boone's Lick, Missouri. In 1826, Carson took a wagon train to the Santa Fe, New Mexico, area. He worked as a fur trapper and got to know the local Indians very well (his first two wives were, respectively, Arapahoe and Cheyenne).

John C. Fremont hired him as a guide on a expedition to map the trails to the Pacific Ocean (1843-1844). Carson led Fremont to Oregon and California, traveling across the central Rocky Mountains, through the Great Basin, and across the Sierra Nevada Mountains. Fremont wrote of this trip, making Carson a national hero.

Carson fought in the Mexican-American War (1846) and later served President James Polk carrying important messages. Carson fought in the Civil War and helped organize the 1st New Mexican Volunteer Infantry of the Union Army (mostly fighting the local Navajo Indians). It was during the Civil War that Carson learned how to read and write.

In 1863, Carson, his soldiers, and some Indian tribes who were old enemies of the Navajo went through the Navajo villages, destroying their crops and livestock. The Navajo surrendered in 1864, and were led on the "Long Walk," a 300-mile trek from Arizona to Fort Sumner, New Mexico, where the remaining Navajo were imprisoned until 1868.

Carson became a brigadier general in 1865. In 1866 he moved to Colorado where he commanded Fort Garland and was a rancher. Carson died in Fort Lyons, Colorado, on May 23, 1868.