Louis Hartmann was born in 1841 in Württemberg, Germany.
Louis left Germany in the late 1850s, and immigrated to the United States, eventually settling in western Michigan where by 1860 he was working as a shoemaker and living at the Bridge Street House in Grand Rapids’ Second Ward. (He was sharing his quarters were one Canadian, two Irishmen, one Englishman, one Pennsylvanian, two New Yorkers, and two Germans also from Württemberg.)
He was 20 years old and residing in Grand Rapids when he enlisted with his parents’ consent in Company C on May 13, 1861. (Company C was made up largely of German and Dutch immigrants, many of whom lived on the west side of the Grand River in Grand Rapids. This company was the descendant of the old Grand Rapids Rifles, also known as the “German Rifles,” a prewar local militia company composed solely of German troopers.) He was wounded on August 29, 1862, at Second Bull Run.
He was absent sick in a hospital from August through September, and died of his wounds on September 18 or October 31, 1862, at Armory Square hospital in Washington, DC. He was buried in the Military Asylum cemetery (Soldier's Home National cemetery), section C no. 3212.