C.A. Tilt started manufacturing passenger cars in 1907. In 1911, one of Tilt’s customers asked Tilt to make a truck. Tilt complied, building the first Diamond T. In 1916, Tilt opened new facilities in southwest Chicago to replace his older buildings on the North side. The new facility would produce 1,500 3-ton Liberty trucks during WWI.  After the war, the military would order an additional 2,000 trucks.

Using the money from government contracts, the company expanded during the 1920s, offering a variety of models at different weight classes that ranged from a 1-ton up to a six-wheeled, 12-ton model. In 1936, Diamond T created a new light diesel line of trucks.

The one-ton Model 201 was introduced in 1938 and was virtually unchanged until 1949 when the less popular Model 222 replaced it. In 1942, Diamond T, like many automotive companies during WWII, turned to producing military vehicles.  More than 50,000 trucks, of all models, were sold to the military. C.A. Tilt retired from the company in 1946. In 1947, Diamond T sold 10,475 trucks. In 1948, the company peaked production with a record of 10,651 vehicles sold. In 1958, the White Motor Company purchased Diamond T.

1947 Diamond T Pickup