Uncle Sam is a popular U.S. symbol usually associated with a cartoon figure having long white hair and chin whiskers dressed in a swallow-tailed coat, vest, tall hat, and striped trousers. His appearance is derived from two earlier symbolic figures in American folklore — Brother Jonathan and Yankee Doodle.
In the late 1860s and 1870s, political cartoonist Thomas Nast (1840-1902) began popularizing the image of Uncle Sam. Nast continued to evolve the image, eventually giving Sam the white beard and stars-and-stripes suit that are associated with the character today.
Perhaps the most famous image of Uncle Sam was created by artist James Montgomery Flagg (1877-1960). In Flagg's version, Uncle Sam wears a tall top hat and blue jacket and is pointing straight ahead at the viewer. During World War I, this portrait of Sam with the words "I Want You For The U.S. Army" was used as a recruiting poster.