Early and mid-20th century American cookbooks offer plenty of sloppy joe-type recipes, though they go by different names: Toasted Deviled Hamburgers, Chopped Meat Sandwiches, Spanish Hamburgers, Hamburg a la Creole, Beef Mironton, and Minced Beef Spanish Style.
Marilyn Brown, Director of the Consumer Test Kitchen at H.J. Heinz in Pittsburgh, says their research at the Carnegie Library suggests that the sloppy joe’s origins lie with the “loose meat sandwiches” sold in Sioux City, Iowa, in the 1930s and were the creation of a cook named Joe.
References to sloppy joes as sandwiches begin by the 1940s. One example from Ohio is a 1944 Coshocton Tribune ad under the heading “‘Good Things to Eat’ says ‘Sloppy Joes’ – 10c – Originated in Cuba – You’ll ask for more – The Hamburg Shop” and elsewhere on the same page, “Hap is introducing that new sandwich at The Hamburg Shop – Sloppy Joes – 10c”.
The term sloppy joe’s had an earlier definition of any cheap restaurant or lunch counter serving cheap food quickly or of a type of casual clothing.