At the outbreak of the
American Civil War, Young joined up as a private with a company of volunteers which was enrolled as Company E of the
17th Wisconsin Infantry Regiment. But shortly after that regiment mustered into service, he was transferred to the
14th Wisconsin Infantry Regiment and commissioned as
first lieutenant of Company H in that regiment. He joined the 14th Wisconsin Infantry as it was still being organized near
Savannah, Tennessee; from there, they were summoned to the nearby
Battle of Shiloh, which had begun unexpectedly. They arrived at the battlefield on the evening of the first day of the battle, and were then engaged in heavy fighting throughout the second day—charging and seizing an enemy battery, suffering 146 casualties (out of about 600 men active at the time). Due to a large number of wounded or killed officers, Young became acting
adjutant of the regiment shortly after the battle, and was formally promoted to adjutant in September 1862 (retroactive to July 1862), and ultimately served in that role until May 1863. During this time, the regiment was engaged in operations for control of the Tennessee–Mississippi border, and then joined Grant's
Vicksburg Campaign. During the Vicksburg campaign, Young was detached from his regiment to assist in recruiting freed Africans to serve in
Union Army regiments. In May 1863, he was commissioned
lieutenant colonel of the
10th Louisiana Infantry Regiment—which later became the
48th United States Colored Infantry Regiment. He assisted in organizing this regiment until October 1863, when he was promoted to colonel and placed in command of the 11th Louisiana Infantry Regiment, which then became the
49th United States Colored Infantry Regiment in March 1864. In this role, he became a brigade commander of forces posted around Vicksburg after the city fell to the Union and was formally appointed
provost marshal of the western district of Mississippi, serving in that role through most of 1864, all of 1865, and into 1866. He was honorably discharged in June 1866. ==Postbellum career==