Addison Gazlay Warner was born and grew up in New York, probably around New Berlin, Chenango County, with his parents, Benjamin Warner and Sarah Sallie Gazlay, and his sister Harriet. By 1860 he was working as a school teacher in Windham County, Connecticut, and was living with Harriet, her husband William Mathewson and William’s parents. On 22 April, 1861, just ten days after the outbreak of the Civil War, Addison left his home in Woodstock, Connecticut, enlisted as a private, and on 7 May of the same year, he joined Company Rifle A, Second Infantry Regiment, Connecticut.

His regiment first saw duty at Camp Corcoran in the defense of Washington, D.C. In the first few days of June, 1861, they advanced to Vienna and Falls Church, Virginia, and stood picket duty there until July 16th. They advanced on Manassas, Virginia, during July 16-21, including the occupation of Fairfax Court House on July 17th. The regiment participated in the Battle of Bull Run (a.k.a. Battle of First Manassas) on July 21st. Addison was mustered out on 7 August 1861 in New Haven, Connecticut, along with the rest of his regiment.

Although the exact date is not known, Addison probably married his wife Angeline Elizabeth Gleason, daughter of Guy Gleason and Pamela Combs, shortly after his return to Putnam, Connecticut. In May of the following year, their daughter Pamelia was born.

On 30 December 1863, Addison was promoted to Full Captain, of Company I, 1st Cavalry Regiment, where he recruited more than one hundred men, and as a result was commissioned a Captain on 29 January 1864.

The Battle of Ashland, on 1 June 1864 found the 1st Connecticut Cavalry, along with other Union regiments, nearly surrounded by Confederate forces in the town of Ashland, Virginia, north of Richmond. The following contemporary account of the battle, from The Military and Civil History of Connecticut During the War of 1861-1865, by W. A. Croffut and John M. Morris, describes Captain Addison G. Warner’s bravery and how he died.

Confederate rebels charged down two of the roads on Warner’s position, but his squadron resisted the onset, and turned it back. The rebels mounted another charge. Captain Warner was shot through the body. Though mortally wounded, he kept his saddle, and continued to rally and cheer on his men with determined and extraordinary courage. He soon received another wound, when, faint from loss of blood, he fell from his horse, and died gloriously.

Addison enlisted as a private in the three-months’ service, and, on returning, taught a private school in Putnam, where he married. He attained much popularity and success as a teacher; exhibiting tact, enthusiasm, and patience combined. But the call to the field was irresistible; and, having recruited more than one hundred men for the First Cavalry, he was commissioned captain in January, 1864. He was constitutionally and from principle a brave man. Sergeant Alexander McDonald of Norfolk, who assisted him on the field after he was wounded, writes the following thrilling account:—

Capt. Warner, says Col. Blakeslee, was “brave to a fault, active, energetic, and faithful: he was also in a peculiar manner the friend of his men. He spared no labor for them, and secured a remarkably strong hold upon their confidence and esteem. His loss was sincerely mourned in the regiment.”

Captain Warner was eventually reburied, in Grove Street Cemetery, Putnam, Connecticut. In the same town, Post 54 of the Grand Army of the Republic was established 13 April 1882, and named in loving memory of one of Putnam’s honored heroes, Addison G. Warner, Captain Company I, First Connecticut Cavalry, slain at the head of his company in Ashland, Virginia, 1 June 1864.

Addison’s wife Angeline evenually remarried, first in 1868 to David M. Gazlay, and after David’s death in 1877, to Henry Martin Gazlay in 1878. Both David and Henry were Addison’s uncles, i.e., brothers of Addison’s mother Sarah Sallie Gazlay.