The 21st Iowa Volunteer Infantry had many who enlisted in early 1862 (the "early enlistees") while most enlisted in July and August 1862. The regiment was mustered in on September 9, 1862. As its ranks were depleted by war, more men were needed and James Firman was one of the "recruits" who joined after the original organization of the regiment. The "early enlistees" were mustered out at Shreveport on June 10, 1865, while others in the regiment arrived in Baton Rouge on June 23, 1865 and camped while officers completed Muster-out Rolls and Descriptive Books for the remaining original enlistees, but Henry Firman and other recruits still had time to serve and were transferred on July 12th as unassigned recruits in a 34th/38th Consolidated Regiment. On the 14th they left by transport for Galveston, Texas. The War Department soon realized their service was no longer needed and on August 15, 1865, they were mustered out at Houston, Texas. His obituary indicates he spent three years in Kansas and Nebraska before returning to Iowa and, on September 3, 1874, he and Annette A. Pomeroy were married at Forestville.

The 21st Iowa Volunteer Infantry had many who enlisted in early 1862 (the "early enlistees") while most enlisted in July and August 1862. The regiment was mustered in on September 9, 1862. As its ranks were depleted by war, more men were needed and James Firman was one of the "recruits" who joined after the original organization of the regiment. The "early enlistees" were mustered out at Shreveport on June 10, 1865, while others in the regiment arrived in Baton Rouge on June 23, 1865 and camped while officers completed Muster-out Rolls and Descriptive Books for the remaining original enlistees, but Henry Firman and other recruits still had time to serve and were transferred on July 12th as unassigned recruits in a 34th/38th Consolidated Regiment. On the 14th they left by transport for Galveston, Texas. The War Department soon realized their service was no longer needed and on August 15, 1865, they were mustered out at Houston, Texas. His obituary indicates he spent three years in Kansas and Nebraska before returning to Iowa and, on September 3, 1874, he and Annette A. Pomeroy were married at Forestville.