Irvine served as a
brigadier general in the
Continental Army during the
American Revolutionary War and served under General
George Washington, with whom he frequently corresponded. Irvine represented
Pennsylvania in both the
Continental Congress (1787–88) and after the war, in the
United States House of Representatives (1793–1795). He served as a ship's surgeon and settled in Carlisle. He was elected to the Pennsylvania Assembly which granted him a colonel's commission in January 1776 for the purpose of raising the
6th Pennsylvania Regiment. On June 16 of that year he was captured, along with a large number of his fellow officers and men, in Canada at the
Battle of Three Rivers during the
Lake Champlain campaign and was not exchanged until May 6, 1778. Although Lord Cornwallis had already surrendered at Yorktown in October 1781, effectively ending the fighting in the east and virtually ending the war, the conflict on the western frontier continued. Irvine soon learned that the Americans living on the frontier wanted the army to launch an expedition against Detroit to end ongoing British support for the American Indian war parties. Irvine investigated, then wrote to General George Washington, on December 2, 1781, and maintained: ::: "It is, I believe, universally agreed that the only way to keep Indians from harassing the country is to visit them. But we find, by experience, that burning their empty towns has not the desired effect. They can soon build others. They must be followed up and beaten, or the British, whom they draw their support from, totally driven out of their country. I believe if Detroit was demolished, it would be a good step toward giving some, at least, temporary ease to this country." Washington agreed with Irvine's assessment that the British in Detroit had to be neutralized or driven out to effectively end the war in the west. Irvine sent Washington a detailed plan for an offensive in February 1782, that with an estimated 2,000 men, five artillery pieces and a supply caravan, he could move on Detroit and capture it. Subsequently, Irvine convinced Colonel
William Crawford to come out of retirement and lead
an expedition against Indians in villages along the
Sandusky River, which ended in Crawford's brutal execution. The militia troops went back under the command of
John Rose, a Baltic German officer from Estonia. Irvine was commander at
Fort Pitt, replacing Colonel
Daniel Brodhead. Upon assuming command he discovered and later complained about, the poor condition of the garrison at the fort. Upon his arrival to Fort Pitt, he was appalled to find the fort in "a heap of ruins" from annual flooding, and its garrison in such an extremely ragged state. In a letter, dated December 2, 1781, to General Washington Irvine reported, "I never saw troops cut so truly a deplorable, and at the same time despicable, a figure. Indeed, when I arrived, no man would believe from their appearance that they were soldiers..." Maintaining that the fort was untenable Irving wrote to Congress and strongly recommended that a new fort be built four miles down stream near the mouth of
Chartiers Creek by the
Ohio River. Irvine maintained that this location was inapproachable on three sides, no commanding ground on its fourth, and that the proposed location would have command of both the creek and the Ohio River. Congress being nearly bankrupt declined Irvine's proposition and ignored his other recommendations. Irvine soon received a letter of reply from Washington, dated December 18, that he was "not at all surprised", but explained that under the circumstances involving disputes over command, and issue concerning other involved interests, this was to be expected, and as such the decision to relocate must rest with the Congress. Irvine became a member of the Continental Congress in 1786 and was selected with
John Kean and
Nicholas Gilman for settling the accounts of the U.S. Government with the several states. ==Later life==