in august 1861 metzner traveled to indianapolis, indiana, where he enlisted for three years of service in the union army during the american civil war. metzner helped organize lieutenant colonel francis "frank" erdelmeyer's turner company, a part of the 32nd indiana volunteer infantry regiment, also known as indiana's 1st german regiment because most of its members were of german descent. metzner was named first lieutenant, company a, 32nd indiana, effective may 19, 1862; he was promoted to captain on february 4, 1863, and transferred to company k. during metzner's term of service from august 1861 until september 1864, his infantry regiment was attached to the first army of the ohio and the army of the cumberland, and served in the western theater.