May 14, 1898, the battalion was mustered into the volunteer service by Captain Rockefeller, U.S.A. Lieutenant Charles Young, U.S.A., then on duty at Wilberforce University, Wilberforce, Ohio, as professor of military science and tactics, was commissioned by Governor Bushnell as Major commanding the Ninth Battalion, O.V.I., relieving Major Fillmore. In order to enable Lieutenant Young to accept his volunteer commission, he was granted an indefinite leave of absence by the War Department.

May 19, 1898, the command having been ordered to join the Second Army Corps at Camp Russell A. Alger, near Falls Church, Va., left Camp Bushnell and arrived at Camp Alger May 21, 1898.

When Major-General Graham assumed command of the Second Army Corps and organized it into divisions, the battalion was placed in the provisional division. In June (exact date not remembered) the battalion was placed in the Second Brigade, Second Division, being brigaded with the Twelfth Pennsylvania and Seventh Illinois Regiments. The battalion was relieved from the Second Brigade, Second Division and placed in the Second Brigade, First Division, being brigaded with the Eighth Ohio and Sixth Massachusetts.

A New Jersey regiment was relieved from duty as corps headquarters' guard late in June and the Ninth Battalion assigned to that duty. The battalion performed this duty until it was ordered South from Camp Meade, Penn., when it became separated from corps headquarters. Important outposts, such as the entrance to Falls Church and the guarding of the citizens' gardens and property, were under the charge of the command.

When General Garretson's brigade (Second Brigade, First Division, consisting of the Eighth Ohio, Ninth Battalion and Sixth Massachusetts) was ordered to Cuba, General Graham, thinking that his entire Army Corps would soon be ordered to active service, requested the War Department, as the battalion was his headquarters guard, to let the battalion remain with him. (See telegrams Gen. Graham's report to the Secretary of War.) General Graham's request being honored by the department, the battalion was deprived of this chance of seeing active service in foreign fields. The battalion was then attached to the Second Brigade, Second Division, under Brigadier-General Plummer, being brigaded with the First New Jersey, Sixty-fifth New York and Seventh Ohio.

In July the battalion was relieved from this brigade and attached directly to corps headquarters. When the Second Army Corps was ordered to Camp Meade, Penna., the battalion was one of the first to break camp, going with corps headquarters. The battalion left Camp R.A. Alger August 15, 1898, and arrived in camp at Camp George G. Meade, near Middletown, Penna., August 16, 1898. In camp the battalion occupied a position with the signal and engineer corps and hospital, near corps headquarters.

When the Peace Jubilee was held in Philadelphia, the battalion was one of the representative commands from the Second Army Corps, being given the place of honor in the corps in the parade, following immediately General Graham and staff. When the corps was ordered South the battalion was assigned to the Second Brigade under Brigadier-General Ames. The battalion left Camp Meade November 17. Up to this time it had done the guard duty of corps head quarters and was complimented for its efficient work by the commanding general. The battalion arrived in Summerville, S.C., November 21, 1898. It was brigaded with the Fourteenth Pennsylvania and Third Connecticut.

When the battalion arrived in the South the white citizens were not at all favorably disposed toward colored soldiers, and it must be said that the reception was not cordial. But by their orderly conduct and soldierly behavior the men soon won the respect of all, and the battalion was well treated before it left. November 28-29 Major Philip Reade, Inspector General First Division, Second Army Corps, inspected the Ninth Battalion, beginning his duties in that brigade with this inspection. He complimented the battalion for its work both from a practical and theoretical standpoint. Coming to the Fourteenth Pennsylvania he required them to go through certain movements in the extended order drill which not being done entirely to his satisfaction, he sent his orderly to the commanding officer of the Ninth Battalion, requesting him to have his command on the drill ground at once. The battalion fell in and marched to the ground and when presented to the Inspector orders were given for it to go through with certain movements in the extended order drill in the presence of the Pennsylvania regiment. This done, the Inspector dismissed the battalion, highly complimenting Major Young on the efficiency of his command. Just after the visit of the Inspector General, General S.B.M. Young, commanding the Second Army Corps, visited Camp Marion. Orders were sent to Major Young one morning to have his battalion fall in at once, as the General desired to have them drill. By his command the battalion went through the setting-up exercises and battalion drill in close and extended order. The General was so well pleased with the drill that the battalion was exempted from all work during the remainder of the day.

The battalion was ordered to be mustered out January 29, 1899. Lieutenant Geo. W. Van Deusen, First Artillery, who was detailed to muster out the command, hardly spent fifteen minutes in the camp. Major Young had been detai led Assistant Commissary of Musters and signed all discharges for the Ninth Battalion, except for the field and staff, which were signed by Lieutenant Van Deusen. The companies left for their respective cities the same night they were paid. Major Bullis was the paymaster.