Mustered in, September 23, 1861, proceeding immediately to Rolla, Mo., where it encamped until January 14, 1862. It then moved into Arkansas with Osterhaus's Brigade and fought at Pea Ridge, losing in that, its first action, 4 killed, 37 wounded and 27 missing. It then moved with Asboth's Division to Corinth, after which it encamped during the summer at Rienzi, Miss. In the fall it marched to Louisville, where it was assigned to Sheridan's Division in which it fought at Chaplin Hills, losing 9 killed, 64 wounded, and 4 missing. At Stone's River, it was in Sill's (1st) Brigade, Sheridan's (3d) Division, McCook's Corps; General Sill was killed in this battle, whereupon Colonel Greusel took the command of the brigade. The regiment lost at Stone's River, 46 killed, 151 wounded, and 15 missing; total, 212. At Chickamauga the brigade was commanded by General Lytle, the regiment losing in that action, 20 killed, 101 wounded, and 20 missing. In October, 1863, the Thirty-sixth was placed in Steedman's (1st) Brigade, Sheridan's (2d) Division, Fourth Corps, in which command it fought at Missionary Ridge. It served in the Fourth Corps during the remaining two years of its service. General Newton commanded this division on the Atlanta campaign, during which Colonel Miller was killed at Kenesaw Mountain. The brigade, under command of Colonel Emerson Opdycke (125th Ohio), achieved a brilliant success at the battle of Franklin, where it captured ten flags and rendered efficient aid at a critical period of the fight; Lieutenant-Colonel Porter C. Olson was killed in this action. The regiment was mustered out in Texas, in October, 1865.