At the outbreak of the
American Civil War, Hall volunteered for service with the
Union Army and was enrolled as a private in Company D,
2nd Minnesota Infantry Regiment. With this regiment, he served in the
Army of the Cumberland in the
western theater of the war and was promoted to corporal and then first sergeant. In the campaign for control of Middle Tennessee, he participated in the battles of
Mill Springs,
Perryville,
Hoover's Gap, and
Chickamauga. At Chickamauga, he was shot in the torso and left for dead on the battlefield. He survived and was captured, but was paroled after just ten days of captivity. He returned to his regiment near
Resaca, Georgia, where he joined the
Atlanta campaign. During this campaign, his three-year enlistment expired and he returned to Minnesota. He assisted in recruiting new volunteers for the
11th Minnesota Infantry Regiment and was commissioned as 1st lieutenant for Company G of the regiment. He returned to the field with the new regiment in the Fall of 1864 and was appointed
provost marshal at
Gallatin, Tennessee, where he remained until the end of the war. ==Postbellum career==