Before the Antietam Campaign:
Prior service in Company D, Twenty-first N. Y. Infantry. Age 23 at enrollment, he mustered in as First Lieutenant, Company B, 63rd New York Infantry on February 27, 1862. Discharged on March 10, 1862. Mustered in as First Lieutenant, same company, on March 25, 1862.

In the Antietam Campaign:
He was mortally wounded in action on 17 September 1862.

The remainder of the War:
He died of his wounds on October 13, 1862, at Buffalo, N. Y.

Lieutenant James MacKey was son to Dr. MacKey, Buffalo. He joined the Sixty-third regiment, and was soon transferred to General Meagher's staff, and was mortally wounded at the Battle of Antietam while carrying orders from the general. He was removed to the hospital at Frederick, and was subsequently brought home by easy stages, by his father, who was anxiously attending him. Though he had apparently rallied, he finally sank and died, on the 17th of October, just a month from the day he had received his wound. He was a brave young officer, and an intelligent, courteous young man, whose services were appreciated by his general, and whose amiable qualities made him a general favorite.

James E Mackay