The jacket had buttons down the front of it which was not part of the original French zouave uniform.

The regiment was first mustered by Stephen W. Stryker, a former lieutenant in the 11th New York Volunteer Infantry Regiment, in part to remember his former commander, Colonel Elmer Ellsworth in Alexandria, Virginia, the first officer to die in the war.

Several other members of the regiments were members of Ellsworth's Chicago Zouave Cadets, including Colonel Freeman Conner, Major Edward B. Knox and Captain Lucius Larrabee, who commanded Company B and was killed at Gettysburg.

During the Battle of Gaines' Mill Col. Rice captured a rebel flag with the inscription “Seven Pines.”[2] They were one of four regiments in the 3rd Brigade, 1st Division, V Corps, Army of the Potomac, commanded by lieutenant colonel Strong Vincent, which fought during the Battle of Gettysburg.

On July 2, 1863, at around 4:00 p.m., the second day of the battle, the 3rd Brigade began a heroic defense of Little Round Top, the extreme left flank of the Union Line.