Holabird served as quartermaster of the Union Army encampment in
Harrisburg, Pennsylvania from June to August, 1861. He was quartermaster of the camp in
Frederick, Maryland from August, 1861 to July, 1862. He was quartermaster of the division commanded by
Nathaniel P. Banks in July and August 1862, followed by assignment as the quartermaster of the
Army of Virginia's
II Corps. Holabird took part in the
Northern Virginia campaign, then served with the
Army of the Potomac during the
Maryland campaign, including the
Battle of Antietam on September 17, 1862. He was chief quartermaster of the
Department of the Gulf from December 1862 to July 1865, and participated in the
Siege of Port Hudson,
Louisiana from May 25 to July 9, 1863. Holabird became ill in Louisiana and was on sick leave from July 13, 1863, to October 1, 1865. While he recovered, Holabird translated
Antoine-Henri Jomini's
Treatise on Grand Military Operations from French to English, enabling the U.S. military to make use of Jomini's work. He served as depot quartermaster in
New Orleans from October 1 to December 16, 1865. From October 1, 1865, to March 7, 1866, Holabird was the chief quartermaster of the Department of Louisiana. Holabird received a
brevet promotion to
major to recognize his distinguished service and he was promoted to the permanent rank of major on July 2, 1862. He received a temporary promotion to
colonel on July 11, 1862. At the end of the war, he received brevet promotions to
lieutenant colonel, colonel, and
brigadier general to recognize the superior service he displayed during the course of the war. ==Post-Civil War==