The regiment was accepted into the Confederate States Army on 1 December under West Point graduate Samuel B. Maxey of Paris, Texas as colonel.

[1] Captain James Hill formed a cavalry company on 10 June 1861 and drilled it near a persimmon grove at Petty, Texas.

[1] On 26 March 1862 at Corinth, Mississippi the 9th Texas was assigned to James Patton Anderson's brigade in Daniel Ruggles's division from Braxton Bragg's II Corps.

The brigade was soon in the front line where it drove the Union right wing back and overran two enemy batteries.

After Shiloh, the regiment was reorganized with a new colonel, William Hugh Young, a 24 year old graduate of the University of Virginia.

[1] At the Battle of Perryville on 6 October 1862, the 9th Texas was assigned to Preston Smith's brigade in Benjamin F. Cheatham's division.

After being repulsed in its attack on Philip Sheridan's Union division, Samuel Powell's brigade fell back across the Chaplin River.

[7] On the morning of 7 October, as Preston Smith's brigade began to march away from the battlefield, Federal artillery fire killed one Texan.

[8] At the Battle of Stones River on 31 December 1862 – 2 January 1863, the regiment was in the brigade led by Alfred Jefferson Vaughan Jr.

After being posted near Shelbyville, Tennessee, the brigade was sent to Mississippi in May in Joseph E. Johnston's unsuccessful attempt to raise the Siege of Vicksburg.

[1] During the Battle of Chickamauga on 19–20 September 1863, Ector's brigade was part of States Rights Gist's division in William H. T. Walker's corps.

In addition to the Texas units, Ector's brigade included Stone's Alabama and Pound's Mississippi Sharpshooter Battalions and the 29th North Carolina Infantry Regiment.

Nathan Bedford Forrest was nearby and quickly fed infantry brigades under Claudius C. Wilson and Ector into the escalating struggle.

Leading the brigade, Young was wounded in a foot which had to be amputated; he was captured and spent the rest of the war in a Federal prison camp.

[1] French's division attacked John M. Corse's Union garrison in Allatoona, Georgia and was repulsed after desperate fighting.

[20] During John Bell Hood's invasion of Tennessee, the brigade missed the Battle of Franklin because it was guarding the army's pontoon bridges.

In this campaign, Edward Canby led 45,000 Federal troops while Dabney H. Maury commanded 10,000 Confederate soldiers and 300 cannons.