It was composed of German citizens with the following field officers: COL Karl Schwarzwälder,LTC Louis Burger, and MAJ George Van Amsberg.

60, of Saturday, April 20, directed MGEN Sandford, commander of 1st Division MYSM, to detail two regiments in addition to the 6th, 7th, 12th and 71st for immediate service, to report forthwith to the President at Washington.

Hearing of this order, the 5th's commander, COL C. Schwarzwälder, offered its service to Governor Edwin D. Morgan Friday, April 19, 1861.

It also ordered Sandford to provide for their immediate transportation to Washington, DC, to report for federal service, and for the issue to them of one month's supplies.

[9] For most of May, a large portion of the remaining three months' service was rendered, particularly at what is termed the "Relay House," where they were employed upon guard, picket and scout duty.

Their duty along the railroad, which was a special object of their care, thwarted attempts to place obstacles upon the tracks to sabotage the arrival of federal volunteers to Washington.

[5] In this respect their services were most valuable, for a large minority of the population of Maryland were inclined to support the Rebellion, that it was necessary to exercise the greatest caution in guarding the lines of communication with the Capital.

On 24 May 1861, the regiment took part in the occupation of Arlington Heights,[10] occupying Camp Union, one mile east of Ball's Crossroads.

At the time of the battle of Bull Run, on Sunday, July 21, it had moved to reinforce the garrison at Harper's Ferry and took station on Bolivar Heights.