He was born in Scotland in 1739.[2][3] In 1775–76, before his war service, he was a timber merchant living in Quebec and sustained financial losses supporting the revolution.[4][5]
After the resignation of Thomas Mifflin, the first quartermaster general, George Washington highly recommended Hay on January 1, 1778, to Henry Laurens, president of the Congress, noting that his generals thought him the "best qualified of any man upon the Continent for the office." However, Congress did not agree, and instead appointed Nathanael Greene quartermaster general on March 2.[8]
On April 15, 1780, his brother, Charles Hay, was arrested by Frederick Haldimand, governor of the Province of Quebec, and not released until May 2, 1783. Udney wrote to Washington to provide a character reference for his case in London.[7]
In 1780, he purchased a house from Hugh Van Kleeck, now called Clinton House, in Poughkeepsie, New York. In 1783, the house was destroyed by fire and he rented the nearby Glebe House. To assist in rebuilding the house, he requested permission from Washington for army craftsmen, which was received.[11][12][13]
In 1794, Hay was in Burlington, Vermont at the time of Lord Dorchester's Speech to the "Seven Villages or Nations of lower Canada." Hay enclosed a copy of speech to Governor George Clinton of New York, which was forwarded directly to George Washington to report on British activities.[19] Dorchester's speech was viewed by many as a potential war provocation from Britain and one of the factors leading up to the Jay Treaty negotiations.[20] During the same year, the Democratic Republican Society of Chittenden County was founded in Burlington, allegedly by Udney Hay. In a published open letter to Alexander Hamilton, Vermont Federalist Nathaniel Chipman derided the formation of the society and the citation of his work to justify its founding:
You have, undoubtedly, noticed the proceedings of the Democratic Society in the county of Chittenden, in this state. I find they have been published with great avidity in New York and Philadelphia. The founder of that society, and sole author of their late proceedings [Udney Hay], perhaps you are apprized, is not an inhabitant of this state, but resides, generally in the city of New York. What could have induced that gentleman to call in the aid of my name or my writings, in support of such proceedings, is best known to himself. If you have not read the work from which the quotations are made, you might be led, from the detached sentences there cited, to believe that it contains the principles of anarchy instead of the principles of government—principles wholly subversive of a representative democracy…[21]
In 1795, Hay served as a second for Commodore James Nicholson in New York during the lead-up to a proposed duel between Nicholson and Alexander Hamilton. The dispute was resolved through negotiation between Hamilton's and Nicholson's seconds.[22]
^George Washington Papers, Series 4, General Correspondence: Udny Hay to George Clinton. 1794. Manuscript/Mixed Material. Retrieved from the Library of Congress, <www.loc.gov/item/mgw438507/>.
^“To Alexander Hamilton from Nathaniel Chipman, 9 [June] 1794,” Founders Online, National Archives, https://founders.archives.gov/documents/Hamilton/01-16-02-0415 . [Original source: The Papers of Alexander Hamilton, vol. 16, February 1794 – July 1794, ed. Harold C. Syrett. New York: Columbia University Press, 1972, pp. 465–470.]