The regiment was organized in February 1862 by merging three independent cavalry battalions.

The 6th Missouri Cavalry Regiment was formed on 14 February 1862 by combining the battalions of Major Clark Wright, Major Samuel Newitt Wood, and Captain Henry D. Hawkins.

Wood resigned on 12 August 1862 and was replaced as lieutenant colonel the following day by T. A. Switzler.

Hawkins resigned on 5 May 1863 and was replaced as major the next day by Bacon Montgomery.

1st Brigade, 3rd Cavalry Division, District of Eastern Arkansas, to January 1863 (6 companies).

1st Brigade, 2nd Cavalry Division, XIII Corps, Department of the Tennessee, to April 1863 (6 companies).

Headquarters, XIII Corps, Army of the Tennessee, to August 1863 (6 companies).

Cavalry Brigade, XIII Corps, Department of the Gulf, to November 1863 (6 companies).

3rd Brigade, Cavalry Division, Department of the Gulf, to January 1864 (7 companies).

1st Brigade, Cavalry Division, Department of the Gulf, to December 1864.

Separate Brigade, District of Baton Rouge, Louisiana, Department of the Gulf, February 1865 (7 companies).

Cavalry Brigade, District of Baton Rouge, Louisiana, to July 1865.

2nd Brigade, 2nd Division, Army of the Frontier, Department of the Missouri, to June 1863.

Scout through Gadfly, Newtonia, Granby, Neosho, and Valley of Indian Creek and skirmish April 8.

Expedition from Milliken's Bend to Dallas Station and Delhi December 25–26, 1862.

Expedition over Boston Mountains to Van Buren, Ark., December 27–29 (2nd Battalion).

Expedition from Young's Point, La., to Greenville, Miss., and Cypress Bend, Ark., February 14–29.

Attack on Bloomfield, Mo., and pursuit to Brown's Ferry November 29–30 (2nd Battalion).

Branchville, Ivey's Ford, Pine Bluff, January 19 (detachment).

Bayou Rapides Bridge and McNutt's Hill, Alexandria, April 27–28.

Operations in southeast Missouri and northeast Arkansas July 18-August 6 (2nd Battalion).

Operations in southwest Missouri and northwest Arkansas August 15–24 (2nd Battalion).

Expedition from Baton Rouge to Clinton, Greensburg, Osyke, and Camp Moore October 5–9.

Davidson's Expedition from Baton Rouge against Mobile & Ohio Railroad November 27-December 3.

Expedition from Baton Rouge to Clinton and Comite River March 30-April 2, 1865.

Duty in District of Baton Rouge, La., until July and the Department of Texas until September.