Fred and August Duesenberg had built aircraft and marine engines during World War I and applied that expertise to racing engines and then to a production car. Two separate organisations were established: the Duesenberg Automobiles and Motors Company, incorporated in Delaware, handled manufacture and sales, while Duesenberg Brothers, a distinct entity, built racing cars and engines.
The Duesenberg Straight Eight was unveiled in late 1920 at the Commodore Hotel in New York City, but production did not begin until late 1921. Fred Duesenberg decided to redesign several key aspects of the car after the public introduction, most significantly changing the valvetrain from horizontal overhead valves — as used in earlier Duesenberg marine and racing engines — to a shaft-driven single overhead camshaft. Simultaneously, the company relocated its headquarters and manufacturing facilities from Newark, New Jersey, to Indianapolis, Indiana, a move completed in May 1921 but adding further delay to the production timeline.
The straight-eight engine had a cast iron block, a detachable cast iron cylinder head with hemispherical combustion chambers, and an aluminium lower crankcase and oil pan. The crankshaft ran in three main bearings. With a bore of 2.875 inches and a stroke of 5 inches, displacement was 260 cubic inches (4.3 litres). At the standard compression ratio of five to one, the engine produced 88 hp at 3,600 rpm and 170 lb-ft of torque at 1,500 rpm, giving a top speed of 71 mph. A single updraft carburetor fed the mixture through a passage in the engine block to the intake manifold on the opposite side; ignition was by Delco coil and breaker points. The transmission was an unsynchronised three-speed gearbox with a single dry-plate clutch.
The chassis was a pressed steel ladder frame with channel-section side members. Suspension at both ends used semi-elliptic leaf springs with Watson Stabilator dampers, and a tubular beam axle at the front. Standard wheelbase was 134 inches, extended to 141 inches for seven-passenger coachwork.
The braking system was the car's most historically significant engineering achievement. The Duesenberg Straight Eight was the first production automobile to fit Lockheed hydraulic brakes on all four wheels. Front brake drums measured 16 inches in diameter and were finned for heat dissipation; the fluid was a mixture of glycerine and water.
The initial production target was 100 cars per month, a figure the company never approached. Fewer than 150 had been built by the end of 1922 after slightly more than a year of production. The company was placed in receivership in January 1924 and restructured as the Duesenberg Motor Company in February 1925. Production continued at the Indianapolis factory until October 1926, when E. L. Cord purchased the company. By that point approximately 650 Straight Eights had been built.
The Model A was succeeded in 1927 by the Model X, a larger derivative with a non-crossflow cylinder head delivering 100 hp, built in a production run of approximately twelve units. Both the Model A and Model X were subsequently overshadowed by the Model J of 1928, a car of such prestige that it retroactively lent the Model A its letter designation when the J needed a predecessor to refer to.
Despite its pioneering status — hydraulic four-wheel brakes and the first straight-eight in American series production — the Duesenberg Straight Eight has remained obscure compared to the Model J. Its technical contributions, however, influenced American luxury car engineering through the late 1920s and established Duesenberg as a manufacturer willing to apply racing and aircraft engine knowledge directly to road cars.