The commissioned officers were:

Colonel David Hunter, Lieutenant Colonel William H. Emory, Majors D. H. Rucker and E. H. Wright.
Captains I. N. Moore, A. V. Kautz, A. W. Evans, Wm. S. Abert, D. McM. Gregg, J. H. Taylor, J. I. Gregg, John Savage, G. C. Cram, C. R. Lowell, J. S. Brisbin, and H. B. Hayes.
First Lieutenants J. K. Mizner, W. W. Averill, H. M. Enos, I. W. Claflin, S. H. Brown, B. T. Hutchins, H. T. McLean, Tattnall Paulding, Frederick Dodge, J. B. Johnson, J. F. Wade, M. H. Leavenworth.
Second Lieutenants J. W. Spangler, Peter McGrath, Hugh McQuade, and C. B. McLellan.

Battle of Antietam

The regiment was commanded by Captain William P. Sanders. It was detached as Provost Guard behind the right flank.

Battle of Antietam

The regiment was commanded by Captain Joseph H. McArthur (USMA ’49)

From the brigade marker on the Antietam battlefield:

The Fifth United States Cavalry, Captain Joseph H. McArthur, commanding, crossed the Middle Bridge over the Antietam shortly before noon and took position on the right of the road, its left resting at this point, in support to the Artillery in its front. It was withdrawn across the creek late in the day.

The Sixth United States Cavalry, Captain William P. Sanders, commanding, was detached and deployed in skirmishing order, as a Provost Guard, in rear of the right wing of the Army of the Potomac.

Battle of Brandy Station

Commanded by Captain George C. Cram.

Battle of Gettysburg

The regiment was commanded by Major Samuel H. Starr.

From the monument on the South Cavalry Battlefield at Gettysburg:

July 3 Moved at 12 m. with the Brigade from Emmitsburg to attack the Confederate Right and Rear but was detached from the Brigade to intercept the Confederate wagon train supposed to be near Fairfield or Millerstown. Engaged a superior force of the Confederate Cavalry near Mllerstown and withdrew after heavy loss.

Casualties: killed 6 men; wounded 5 officers and 23 men; missing 5 officers and 203 men

From the markers on Ortanna Road west of Gettysburg:

Here the temporary field hospitals of the regiment of July 3rd 1863. The regiment commanded by Major. S. H.Starr was sent to Fairfield to capture a Confederate wagon train guarded by Jones’ Brigade of Confederate Cavalry consisting of the 6th 7th & 11th Rgt’s Virginia Cavalry, Clue’s Virginia Battery and the 35th Virginia Battalion were met on this road & after a severe hand-to-hand fight were compelled to retire.

Brought into action 400, lost 242.