Organized and mustered into Confederate service for 12 months at Pocahontas on September 23, 1861 under the command of Col. John S. McCarver, Lt. Col. Samuel J. Mason, and Major John H. Kelly. Companies A, B, E, and H were detached from the regiment under Major Kelly's command and designated as the 9th Arkansas Infantry Battalion in January, 1862. The remainder of the regiment was then often referred to as the 18th Arkansas Infantry Battalion. Assigned to Rust's Brigade, Jone's Division, in Earl Van Dorn's Army of the West, where it served in the Corinth Campaign from April to June, 1862. The remaining six companies were consolidated into four on May 14, 1862, and were subsequently consolidated with the 17th (Lemoyne's) Arkansas Infantry on May 14, 1862, and the new organization renamed as the 21st Arkansas Infantry Regiment.
Also Known As: 9th (McCarver's) Arkansas Infantry; 18th Arkansas Infantry Battalion (after January, 1862).