Needing a standard engine that could be readily produced by American manufacturers when entering World War I, Jesse Vincent of Packard Motor Car and Elbert Hall of Hall-Scott Motor Car co-designed the Liberty in a week in mid-1917. They set out to design an engine with maximum power and minimum weight that would lend itself to mass production, and planned a series that would include 4-, 6-, 8-, and 12-cylinder models. To ensure a workable engine in the shortest possible time, they used only proven components. They succeeded with the first 8-cylinder engine delivered in early July.

With demand for lower-power engines already being met, and wartime experience showing the need for high power, only the 12-cylinder model was produced in quantity. The more than 20,000 Liberty-12s manufactured by Packard, Lincoln, Ford, General Motors, and Nordyke and Morman powered many aircraft types, but most were built for the de Havilland DH-4.