During World War I, the auto industry halved domestic production in favor of an outpouring of weaponry and military vehicles. The new Cadillac V-8 became the standard military vehicle in the U.S. army, and GM delivered 90 percent of its trucks, along with many armoured cars and other specialized military vehicles, for war use.

In 1919, in response to pent-up postwar demand, GM set up a financing arm that would help buyers purchase cars in installments. By 1920, the General Motors Acceptance Corporation’s installment plan helped two million people buy new vehicles. The question was no longer whether motor cars would catch on but what kinds of cars people would buy.

The same year, GM acquired dozens of automobile and supplier companies now lost in the past. However, most of GM’s many acquisitions have successful lives within the company, and 1919 saw some that turned out to be crucial investments –such as the Delco Light Company, the Fisher Body Company, Dayton Metal Products, the Dayton-Wright Airplane Company, and the T.W.Warner Company (a gear manufacturer). In 1919 GM also set up its export division and turned out its first Chevrolet trucks.