Albert Sidney Johnston was born in Washington, Kentucky, on 2 February 1803. He was educated at Transylvania University and then at West Point, where he graduated in 1826. Johnston impressed people with his intelligence and demeanor, and, consequently, he managed to climb the ranks rapidly.

He served in the army for many years, and saw action in the Black Hawk War; however, pressures from within his family caused him to resign in 1834. In 1836 he went to Texas to fight in the revolution occurring there. He served as Secretary of War of the Republic of Texas from 1838 to 1840. During the Mexican War Johnston led a Texas volunteer regiment and fought at Monterrey. He was reappointed to the U.S. Army in 1849, and commanded the Department of Texas from 1856 to 1858.