Eddie Rickenbacker drove the first Duesenberg-designed vehicle to race at the Indianapolis 500 in 1914, placing tenth.

During World War I, the Duesenbergs designed and built aircraft engines in Elizabeth, New Jersey.

August's role in the passenger-car side of the business declined after Cord's takeover, and August worked primarily in Duesenberg's racing division after 1926, designing all Duesenberg race cars built from that year until the company's dissolution.

In 1929, the company began selling the Duesenberg Model J, which was powered by a 265-horsepower (198 kW) straight-eight engine.

[11] In 1998, The Franklin Mint started producing collectible scale models of Duesenberg Coupé Simone, a fictitious custom-made luxury car allegedly manufactured in the late 1930s.

[17] The "Duesenberg II" retained the styling of the cars from the 1920s and 1930s, but included some modern updates, such as stereo systems, air conditioning, and an automatic transmission.

[20] The company produced several models, including the Torpedo sedan and phaeton, and the Murphy roadster.

Designed by Jeff Teague, the new 'Duesenberg Torpedo Coupe' would feature a radical axial twelve-cylinder engine layout known as a 'Cylindrical Energy Module' or CEM.

[22] The powerplant would also allegedly create only 1/6th of the heat of a conventional engine, meaning air cooling would be sufficient.

[24]: 51  The Duesenberg Model A introduced several innovative features, such as an overhead camshaft, four-valve cylinder heads, and the first four-wheel hydraulic brakes offered on a passenger car.

[6]: 40  Sales lagged, and Duesenberg could not meet a 100-vehicles-per-month quota as the Indianapolis plant struggled to roll out one a day.

[9] The Duesenberg Model X chassis is an upgrade over the Model A chassis, offering a reworked 260-cubic-inch (4.3 L) straight-8 engine, an overhead cam, with a new crankshaft, revised valve train, improved pistons and superior intake manifold.

Improved leaf springs are mounted above the frame rails, thus, lowering the center of gravity.

[26] The first Model J prototype was created in 1927 and the first cars were delivered in 1929, shortly before the onset of the Great Depression.

[28]: 73  It output 265 horsepower (198 kW), aided by dual overhead camshafts and four valves per cylinder, making it the most powerful car of its time.

Duesenberg historian Randy Ema wrote that the Model J spurred change in engine design, "single-handedly (starting) the horsepower race that drove the number of cylinders from twelve to sixteen," but noted those engines still could not match the Model J's power output.

[9]: 367  A special version of the SJ, the Mormon Meteor, broke several land speed records.

[32] Two modified Model Js, known as the SSJ, were produced in 1935 for actors Gary Cooper and Clark Gable.