His family originally came to America because his father Johannes Weesner migrated to New York in about 1714 along with other Swiss veterans of the English Army who fought under Marlborough in the War of the Spanish Succession. 
Orange County first elected him as a representative to Province of New York Assembly in 1759 and returned him for eleven consecutive years. In 1768 he became a judge in the county's court of common pleas. When New York created a revolutionary government in 1775, Wisner was sent to the New York Provincial Congress. That body, in turn, named him as a delegate to the Continental Congress where he served through 1776. Wisner was in Congress when the Declaration of Independence adopted, but the New York delegation was not authorized to declare independence, and so Wisner could not take part in the voting. The claim made years later that Wisner was the only member of the New York delegation to vote in favor of independence seems to be without foundation; he did not vote because he could not vote. After the New York delegation was finally authorized to support the Declaration, a signing ceremony took place in August 1776, but Wisner was not present in Congress to sign.
While in Congress, Wisner learned that one of the Continental Army's difficulties was obtaining powder and shot. When he returned home he built three gunpowder mills in Orange County. At their height he was shipping 1,000 pounds of gunpowder each week to Washington's army. He later financed the erection of cannon and defensive works overlooking the Hudson River, that blocked the British ability to use the river in the Highlands Region.
In late 1776 Wisner, along with Gilbert Livingston of Poughkeepsie, sounded the Hudson River and, as part of a Secret Committee, recommended the placement of what became known as the Great Chain which stretched from the current location of West Point to Constitution Island. This chain was part of a series of Hudson River Chains designed to thwart British naval movements on the Hudson
In 1777, serving again in the provincial congress, Wisner was a member of the committee that drafted the first constitution for the state of New York. Under that constitution, Wisner was a member of the state senate from 1777 until 1782. After the war he remained active in civic affairs.
In 1784, he founded an Academy in Goshen, and was one of the regents of the University of the State of New York from 1784 to 1787. In 1788, Wisner was a delegate to the state convention called to ratify the U.S. Constitution. He was one of those who opposed ratification, fearing that the strong central government would eventually infringe on state and individual rights.
Family and descendants
Wisner married Sarah Norton in 1739. His son Gabriel, born 1754, died in 1779 in the Battle of Minisink. He married Elizabeth Waters and had three children. His daughter, Sarah Wisner (1745–1810), married Major Moses Phillips, a descendant of the Winthrop family through Elizabeth Fones, and Thomas Cornell (settler), with whom he made gunpowder for George Washington.
- George Franklin Wisner: "The Wisners and Their Kindred in America" 1918
- Robert Ernst. "Wisner, Henry"; American National Biography Online, February 2000.
- Letter from Henry Wisner and Gilbert Livingston to New-York Committee of Safety: Soundings of Hudson river in the Highlands American Archives Series 5, Volume 3, Page 0812 November 22, 1776. http://lincoln.lib.niu.edu/cgi-bin/amarch/getdoc.pl?/var/lib/philologic/databases/amarch/.27283 Accessed November 28, 2014.
- Henry Wisner at Find a Grave