Born to a poor family of Quakers, Burnside was indentured at an early age as a tailor's apprentice. Afterward he entered West Point and graduated in the class of 1847, during the Mexican War. Although sent to Mexico, he did not arrive until the war had ended. Burnside was then ordered to duty in New Mexico, where he was wounded in an engagement with Apaches. During duty in New Mexico, Burnside found the cavalry carbine unsuited for plains service and invented the Burnside breechloading rifle. In 1852 he resigned his commission and settled in Rhode Island to manufacture the new rifle, hoping for a lucrative government contract. After failing to obtain a contract, he was forced to turn over the patent rights to creditors. Still in debt, Burnside found employment with his former West Point classmate George McClellan at the Illinois Central Railroad in Chicago.
By 1860 Burnside was the company treasurer with an office in New York City. At the beginning of the Civil War, Burnside returned to Rhode Island to take command of a regiment of militia, which led to Washington in April 1861. At the Battle of First Bull Run on 21 July, Burnside was a colonel in command of a brigade and by early August had been promoted to brigadier general of volunteers. In early 1862 Burnside commanded an expedition against the North Carolina coast, where his troops captured Roanoke Island, New Berne, Beaufort, and Fort Macon. For these accomplishments he was promoted to major general in March 1862. In July Burnside's troops, plus troops from other commands, were organized into the IX Corps. During the Second Bull Run Campaign the IX Corps was attached to Pope's Army of Virginia, although Burnside himself remained near Fredericksburg. During the Maryland Campaign Burnside was briefly assigned command of a wing, which consisted of the I and IX Corps, in McClellan's army.
Burnside had twice before been offered command of the Army of the Potomac, after the Peninsula and Second Bull Run Campaigns. Each time he had expressed that he did not feel competent to command such a large force. However, in early November President Lincoln relieved McClellan and Burnside reluctantly accepted the command. A month later he crossed his army to the south of the Rappahannock River but was defeated at the Battle of Fredericksburg on 13 December.
In January 1863 Burnside attempted to launch another offensive campaign, known as the Mud March; poor weather conditions resulted in another failure. President Lincoln relieved him of command and transferred him to the Western Theater. While he was commander of the Department of the Ohio, his forces occupied East Tennessee and captured Knoxville. In 1864 Burnside was ordered back east, once again commanding the IX Corps, and participated in Grant's Overland Campaign in Virginia. He led his corps through the Battles of the Wilderness, Spotsylvania, and Cold Harbor and the operations against Petersburg. After the failed attack at the Battle of the Crater at Petersburg in July, Maj. Gen. George G. Meade charged Burnside with disobedience of orders. A court of inquiry found Burnside "answerable for the want of success," and in April 1865 he re
signed from the Army. After the war Burnside was three-time governor of Rhode Island; from 1875 until his death, he served as a U.S. Senator.