Corse joined the
6th Iowa Infantry as its
Major in July 1861 and initially served under
Maj. Gen. John C. Fremont. He then served on the staff of Maj. Gen.
John Pope early the following year during the
Battle of Island Number Ten and associated engagements. He returned to field duty with his regiment and fought in the
Siege of Corinth, being promoted to
lieutenant colonel. He was promoted to
brigadier general of volunteers on August 11, 1863, in recognition of his service at the
Siege of Vicksburg. Assigned command of the 4th Brigade, 4th Division,
XV Corps, in the Federal
Army of the Tennessee, Corse participated in the
Chattanooga campaign. After recuperating from an injury suffered at
Missionary Ridge, Corse returned to active duty as the inspector general on Maj. Gen.
William Tecumseh Sherman's staff. In July 1864, he returned to field duty in command of a
division in
XVI Corps. General Corse is best known for his role in the
Battle of Allatoona in October 1864. On Sherman's orders, Corse went with 2,100 men to secure Allatoona Pass to prevent Confederate Gen.
John Bell Hood from severing Union communications. The small band of Union soldiers fought determinedly against the 7,000 troops under Major General
Samuel G. French. During the bloody battle, Corse "lost one third of his men and one third of his ear" but secured the pass on October 5, the date on which he was later appointed a
brevet major general. In the midst of the fighting, General Corse received the famous message from General Sherman, "Hold on, I am coming!" Newspapers later amended the text to "Hold the fort, for I am coming", which inspired a popular ballad. Corse was badly wounded during the stubborn defense, losing a cheekbone and one ear, but recovered to resume his front-line combat duties. Corse later participated in
Sherman's March to the Sea and the
Siege of Savannah. In the final months of the Civil War, he led his division during the
Carolinas campaign. At the end of the war he was appointed brevet major general for his Allatoona service. ==Postbellum career==