Like most heavy trucks of the era, the AC used solid tires initially, although towards the end of its production run many were delivered with pneumatic tires.

Chain drive was used to drive the rear wheels while the front axle was made of drop-forged alloy steel for extra strength. The AC's pressed chrome-nickel steel chassis was heat-treated for durability. One of the most distinctive features of the AC was its hood and dashboard mounted radiator (mounted behind the engine) which was covered by a squared off bonnet of a coal scuttle pattern which had a small circular grille at the front containing the Mack emblem, all of which gave the model its distinctive appearance. From 1936 Buda and Cummins diesel engines were also offered in the AC. The engine had an aluminum crankcase which included inspection ports, and a governor built into the camshaft timing gear it was driven through a three-speed transmission with a clutch brake. The AC was powered by a pair-cast 4-cylinder petrol engine that delivered 74 brake horsepower (55 kW) (5圆 471.2ci). The AC was a two-wheel drive, two-axle truck which was made in three sizes, with payloads of 3 + 1⁄ 2 long tons (3.6 t), 5 + 1⁄ 2 long tons (5.6 t) and 7 + 1⁄ 2 long tons (7.6 t). When introduced, the AC complimented the smaller AB, another Hewitt design, that was introduced in 1914 to replace Mack's older Junior model. Mack's chief engineer, Edward Hewitt, is credited with designing the AC which on its introduction was so innovative it had 18 patents on various aspects of its design.

Mack introduced the AC model in 1916 to replace their Mack Senior model which dated from 1905.

1920s mack garbage truck