Buschbeck volunteered for service in the Civil War, becoming lieutenant colonel of the 27th Pennsylvania Infantry in September 1861.
As colonel, Buschbeck took part in the Battle of Cross Keys under the command of Maj. Gen. John C. Frémont.
In the Army of the Potomac, Buschbeck served under Franz Sigel and Oliver Otis Howard.
At the Battle of Chancellorsville he commanded 1st Brigade, 2nd Division of the XI Corps under Adolph von Steinwehr.
Buschbeck served with distinction but never received a promotion, even by brevet, to the rank of brigadier general.