Having fought in the American Revolutionary War, his journal is one of the most frequently quoted accounts of the surrender of the British at the siege of Yorktown.

Upon learning that a privateer ship was to sail, with a letter of marque, from Philadelphia for the West Indies, he joined the crew as a volunteer.

[2] This transpired during 1781 as the Continental Army marched south to face Cornwallis at Yorktown, Virginia, as War for Independence drew to a close.

Denny rejoined the army as a lieutenant in the First American Regiment[5] in August 1784, and was active in the Northwest Indian War.

Following the battle, Lt. Denny wrote that the native nations were "an enemy brought up from infancy to war, and perhaps superior to an equal number of the best men that could be taken against them.

"[7] He travelled to Philadelphia to deliver the official report of the loss to Secretary of War Henry Knox and President George Washington.

[8] While in Philadelphia, Denny described encountering friends who "view me as escaped from the dead— astonishment takes place of pleasure; and having in some degree got over those feelings myself, am considered as little better than one of the savages.

Following a mission to report on the condition of Fort Le Boeuf in 1794, Major Denny resigned his commission and settled near Pittsburgh.

One of the first resolutions of the Pittsburgh City Council was that of honoring the patriotic and public service of Ebenezer Denny on learning of his early retirement due to health concerns in 1817.