Uncle Sam was first used in 1916.
James Montgomery Flagg created the iconic illustration of Uncle Sam.
Flagg, an illustrator and portrait artist best known for his commercial art, contributed 46 works in support of the war effort during World War I. Leslie's Weekly first published his illustration of Uncle Sam as the cover of the July 6, 1916, issue with the title "What Are You Doing for Preparedness?"
More than four million copies were printed between 1917 and 1918. The image also was used extensively during World War II.
In 1961, Congress passed a resolution that officially recognized meat packer Samuel Wilson (1766-1854) as Uncle Sam's namesake. Wilson, who supplied meat to the army during the War of 1812, is reputed to have been a man of great fairness, reliability, and honesty who was devoted to his country.