[2] In the fall of 1861, after the outbreak of the American Civil War, Colman assisted in raising a company of volunteers to answer President Abraham Lincoln's call for three-year enlistments.
The regiment arrived around noon on Saturday, April 5, and were assigned to the command of General Benjamin Prentiss, marching the rest of the day to reach his headquarters, going into camp at dusk without supper.
During the night, Confederate forces under Albert Sidney Johnston marched to within two miles of the Union lines and attacked near dawn on Sunday, April 6, the start of the Battle of Shiloh.
Initially, their left was supported by the 15th Michigan Volunteer Infantry Regiment, but they had not yet been supplied with ammunition and were forced to withdraw as a result.
[3]: 657 After about two hours of fighting, the entire division began a retreat, it was around this time that Lieutenant Colman was severely wounded when he was shot in the head.
[4] In 1877, Colman returned to Empire, Wisconsin, and was elected Sheriff of Fond du Lac County for a two-year term, running on the Republican Party ticket.
His sister, Cornelia Colman, married Union Army General Edward S. Bragg, of the 6th Wisconsin Volunteer Infantry Regiment, who later became a U.S.