Uncle Sam is a common national personification of the American government or the United States in general that, according to legend, came into use during the War of 1812 and was supposedly named for Samuel Wilson. Its actual origin is obscure. However ...
The Sam Wilson story was first popularized in an 1830 article in the New York Gazette. It was later made a matter of public record in 1961, when Congress passed a resolution acknowledging Wilson as the “progenitor of America’s national symbol of ‘Uncle Sam.’” Nevertheless, many modern researchers doubt the tale’s veracity. Historian Donald R. Hickey has uncovered a reference to Uncle Sam in a U.S. Navy midshipman’s diary from 1810, which suggests that the term predated the War of 1812. In 1813, meanwhile, Wilson’s hometown newspaper wrote an article that referenced the term, but made no mention of his role in inspiring it. Instead, the story stated that the name was simply a playful take on the “U.S.” that was often emblazoned on military wagons and supplies.
The final step in the character’s transition into a national icon came courtesy of artist James Montgomery Flagg. In 1916, he used his own face as a model for an Uncle Sam cartoon in a periodical called Leslie’s Illustrated Weekly Newspaper. The image, which shows a goateed Uncle Sam pointing straight at the viewer, later appeared in a now-famous World War I recruitment poster featuring the tagline “I Want You For U.S. Army.”
Clancy's comment: Now ya know!