John Loudermilk enlisted in Company K, 18th Regiment, Georgia Volunteer Infantry, Army of Tennessee on June 14, 1861 as a private.
On October 2, 1861 he was appointed Regimental Sergeant Major of the 18th Regiment.
On March 11, 1862 with his rank now that of Captain, John formed Company D, 36th Georgia Regiment, Cummings Brigade, Army of Tennessee.
During his service John participated in many battles including; Cumberland Gap, Perryville, Dog Walk, Baker's Creek, Missionary Ridge, Chattanooga, Lookout Mountain, Pea Vine Creek, Rome, Resaca, Tunnel Hill, Buzzard Roost, Dalton, Adairsville, Dug Gap, Cassville and New Hope Church. John was captured at Baker's Creek, but shortly escaped and rejoined his men after the fall of Vicksburg.
There are many stories to be told about John and his service to the Confederate States of America but one can get the essence of John in letters that were written about him after he made a request to form a regiment of cavalry to operate behind enemy lines, using their familiarity with the land to their advantage.

"Learning that Capt. Loudermilk of the 36th Ga Regt and Lt W. Gray of the 8th Ga Battalion intend to make application for authority to raise a Battalion of Cavalry and being well acquainted with both these officers, I take pleasure in recommending them to favorable consideration of the Department as gentlemen of great energy and courage."
W. G. Wofford
Brig. Genl. (March 17,1864)

"I am also acquainted with Capt. Loudermilk who is a stunning active and efficient officer."
W. W. Smith
Maj Gen (April 12, 1864)

"From long personal acquaintance with Capt Loudermilk and Adjt Gray, I take pleasure in recommending them as good energetic officers.............. I feel certain of their success and much good can be gained the service by rewarding them the privilege."
C. E. Broyles, Maj
Commanding (April 14, 1864)

"Capt Loudermilk & Adjt Gray are gentlemen of merit, energy and courage."
Z. L. Walters
Lt Col 8th Ga Batt(April 11, 1864)

There are many more letters of praise for Captain John and he was appointed to the rank of Major July 6, 1864 (his date of rank was actually April 28,1864). However, John received a head wound at the battle of New Hope Church on June 1, 1864. He was transported to Field Hospital #2, located on the Fairgrounds at Atlanta Georgia where he died from the wound on June 9, 1864. Major John Loudermilk's grave can be found in Oakland Cemetery, Atlanta Georgia. (Section D, Row 2, Grave 46)