After resigning his commission as a first lieutenant of cavalry in the United States Army in 1861, Hood offered his services to the Confederate army. He was commissioned a lieutenant and ordered to report to Richmond, Virginia. Hood soon received promotions to captain, then major. He served for the first time in action at the battle of Yorktown and received a promotion to lieutenant colonel. Within a few months, he was assigned command of the 4th Texas Infantry Regiment, soon to become part of the Texas Brigade. In March 1862, he had attained the rank of brigadier general, in which capacity he served throughout the Peninsula campaign, and at the Battle of Second Manassas. In October 1862, he was promoted to major general. He received command of a division, which he led into the battles of Antietam and Fredericksburg. In the following year, in July 1863, he was wounded at Gettysburg. At the Battle of Chickamauga, he was wounded in the leg, and it was amputated. He was appointed to lieutenant general in February 1864. In July, he took over command of the Army of Tennessee with the temporary rank of a full general. He served throughout the Atlanta campaign before marching his army into Tennessee. He commanded forces at the Battle of Franklin, and subsequent Battle of Nashville. He was relieved of command in January 1865 by his request.