1757–1825, American general and one of the most corrupt and devious officers in the nation's early army, b. Calvert co., Md. Abandoning his medical studies in 1776 to join the army commanded by George Washington, he served as a captain in Benedict Arnold's unsuccessful Quebec campaign. Later he was Gen. Horatio Gates's deputy adjutant general in the Saratoga campaign and was given the honor of bringing to Congress the news of General Burgoyne's defeat. Congress censured Wilkinson for delay in carrying the dispatch but rewarded him by promoting him to brigadier general (1777) and making him secretary to the board of war (1778), a position he was forced to leave because of his implication in the Conway Cabal. He was (1779–81) clothier general of the army but resigned when charged with irregularities in his accounts.
Wilkinson moved to Kentucky in 1784. Shortly thereafter, he became a key figure in the plan to induce what was then the SW United States to form a separate nation allied to Spain. Wilkinson apparently took an oath of allegiance to Spain, received a Spanish pension of $2,000 (and later $4,000) a year, and acted as a secret agent of the Spanish government for many years. To the Spanish authorities in New Orleans he represented his agitation for the separation of Kentucky from Virginia as part of the secession scheme; there is no indication, however, that he revealed any such motivation to the Kentucky conventions, in which others had expressed sentiments in favor of a separate republic of Kentucky.
In 1791, Wilkinson reentered the army as a lieutenant colonel, and in 1792 he again attained the rank of brigadier general, serving under Anthony Wayne. On Wayne's death (1796) Wilkinson became (1797) commander in chief of the entire army, even though he was still in the pay of the Spanish. While governor (1805–6) of the Louisiana Territory, he became involved in the schemes of Aaron Burr. Alarmed when he realized that his association with Burr was common knowledge, Wilkinson informed President Jefferson that Burr was plotting to disrupt the Union. Although he was chief prosecution witness at Burr's trial, he narrowly escaped indictment. Subsequently (1811) he was cleared, but just barely, by an army board of inquiry. In the War of 1812 as supreme commander on the Canadian frontier, he failed signally in the campaign to take Montreal and was relieved of his command. Once again an official inquiry left him untouched. He wrote Memoirs of My Own Times (3 vol., 1816) in an attempt to answer his many critics. He died in Mexico, where he spent his last years.