“Uncle Sam” is the most common national personification of the U.S. government (his initials U.S. are the same as the abbreviation for the country’s name), typically shown as an elderly man wearing a white top hat with white stars on a blue band, a blue tail coat, and red trousers.
His origins can allegedly be traced to the War of 1812, more precisely to Samuel Wilson, a meat packer from Troy, New York, the co-owner of the company who supplied the soldiers’ rations. At that time, contractors were required to stamp their name and the place of the food’s origin onto the food they were sending.
Allegedly, soldiers joked that the initials U.S. on the barrels (actually referring to the United States) referred to “Uncle Sam”, as Samuel Wilson was often called. With time, anything marked with these initials (i.e. pretty much all Army property) became associated with his name, which thus became an euphemism for the U.S. government. In 1961, U.S. Congress officially recognized Sam Wilson as the progenitor of the “Uncle Sam” icon.
However, there are several claims that the name is actually older. For example, many believe “Uncle Sam” an alternative name for the similar-looking “Brother Jonathan”, another personification which was common during the American War of Independence.
In time, however, “Brother Jonathan” became less popular, and his role was slowly taken over by “Uncle Sam”. Furthermore, an “uncle Sam” as a personification of the government is mentioned by U.S. Navy officer Isaac Mayo in a journal entry dated 1810.
In any case, the “Uncle Sam” we know today appeared quite some time later, on the famous recruitment poster for World War I (“I want you for U.S. Army”), made by James Montgomery Flagg, clearly inspired by a British recruitment poster which showed Lord Kitchener in a similar pose. Flagg used his own face as a model for the “Uncle Sam” shown on that poster.