Some trace the modern history of fast food in the United States to 7 July 1912, with the opening of a fast food restaurant called the Automat in New York. The Automat was a cafeteria with its prepared foods behind small glass windows and coin-operated slots. Joseph Horn and Frank Hardart had already opened the first Horn & Hardart Automat in Philadelphia in 1902, but their "Automat" at Broadway and 13th Street, in New York City, created a sensation. Numerous Automat restaurants were built around the country to deal with the demand. Automats remained extremely popular throughout the 1920s and 1930s. The company also popularized the notion of "take-out" food, with their slogan "Less work for Mother".

Most historians agree that the American company White Castle was the first fast-food outlet starting in Wichita, Kansas in 1916 with food stands and founding in 1921, selling hamburgers for five cents apiece from its inception and spawning numerous competitors and emulators. What is certain, however, is that White Castle made the first significant effort to standardize the food production in, look of, and operation of fast-food hamburger restaurants. William Ingram's and Walter Anderson's White Castle System created the first fast food supply chain to provide meat, buns, paper goods, and other supplies to their restaurants, pioneered the concept of the multi-state hamburger restaurant chain, standardized the look and construction of the restaurants themselves, and even developed a construction division that manufactured and built the chain's prefabricated restaurant buildings. The McDonald's Speedee Service System and, much later, Ray Kroc's McDonald's outlets and Hamburger University all built on principles, systems and practices that White Castle had already established between 1923 and 1932.