Devout Porsche enthusiasts are well-versed in the marque’s heroes. They can cite chapter and verse about Ferdinand and his son, Ferry. The roles Dr. Anton Piëch, Ferdinand’s son-in-law, and his descendants played founding and nurturing this brand are well documented. In the modern era, Hans Mezger’s brilliant engine contributions are core to the Porsche legend. But any mention of Adolf Rosenberger draws blank stares from the Zuffenhausen faithful. Here, we set the record straight on his place in the Porsche lore.

Rosenberger was born in Pforzheim, Germany, in 1900. Success in cinema and real-estate businesses made his family wealthy, providing the young Rosenberger the means to pursue his passion for motorsports—first on motorcycles, then racing the fastest sports cars available in Germany. The Benz RH (Rennwagen Heckmotor, or rear-engine racer), more commonly called the Tropfenwagen, left an indelible impression on Rosenberger. In 1924 and ’25, he won the Solitude road race held near Stuttgart driving this radically ahead of its time, teardrop-shaped, mid-engine sports car.
In 1926, Rosenberger and Rudolf Caracciola both drove front-engined Mercedes SSs designed by the firm’s technical director Ferdinand Porsche at the first German Grand Prix held at AVUS. Rosenberger was quicker on the wet track but was overcome by fumes leaking from an onboard ether tank used to start the supercharged six-cylinder engine. He passed out and crashed into a timing hut, killing three course marshals.
By the time Rosenberger and Caracciola faced off for the 1927 Eifelrennen, the first major sports car race held at the Nürburgring, Rosenberger had 40 victories under his belt. He and his archrival both drove Mercedes SSKs in the over 5000 cc class. Rosenberger finished a close second to Caracciola, who went on to earn three European Grand Prix Championships for the three-pointed star in the 1930s.
Mercedes and Benz joined forces in 1926, by which time Rosenberger was well acquainted with Ferdinand Porsche. When Porsche’s ideas fell out of favor at Daimler-Benz, he returned to his Austrian homeland to work briefly at Steyr before establishing his independent design office in Stuttgart.

The doors at Kronenstraße 24 opened late in 1930 for an enterprise called Dr. Ing. h.c. Ferdinand Porsche GmbH, Konstruktionsbüro für Motoren- und Fahrzeugbau (design office for engine and motor vehicle construction) with a total of nine designers, including his son, Ferry. Rosenberger served as the managing director. The elder Porsche supplied 80 percent of the seed money while Rosenberger and Dr. Piëch each contributed 10 percent, or 3000 RM to the cause (approximately $700 in 1930, about $17,000 today). While the enterprise was successful from the start, when customers were slow to pay, engineers took home partial salaries. On one occasion, Rosenberger provided an additional 80,000 RM (nearly $280,000 today) to sustain operations.
The money man also supplied inspiration. In 1932, Dr. Porsche resorted to his favorite endeavor, designing race cars, with an eye toward the 750-kg (maximum weight) grand prix formula scheduled for implementation in 1934. In an interview with author Griffith Borgeson, Rosenberger recalled vivid memories of the Benz RH: “I happen to have been the first person to drive those cars to success in racing and had a good idea of their good and bad points. They had only 65 horsepower but in one of the Solitude races we beat one of the 125 horsepower blown Mercedes. It was my experience driving that baby that led us to design a rear-engine car.” In other words, Rosenberger was instrumental in convincing the Porsche design team—Dr. Porsche, chief engineer Karl Rabe, and engine expert Josef Kales—that locating the engine behind the driver in Porsche’s speculative grand prix racer was the way to go.
The initial configuration for what would become Auto Union’s Type A racer specified a mid-mounted supercharged 4.4-liter V-16 producing 290 horsepower and a 182-mph top speed. The mid-engine configuration provided several advantages over conventional rivals: a greater load on the drive wheels, a larger engine due to the tidy powerplant/transaxle integration, and minimal change in balance as the fuel was consumed. Rosenberger’s friendship with Auto Union board chairman Baron Klaus-Detlof von Oertzen was instrumental in selling the speculative design to the Audi, DKW, Horch, and Wanderer combine.

Unfortunately, a black cloud hung over Rosenberger. When the other Adolf became Germany’s chancellor in January 1933, it became clear to Rosenberger that his Jewish heritage was a distinct liability. He resigned from Porsche and transferred his ownership share and management responsibilities to a close friend, Baron Hans Veyder-Malberg. In spite of the fact that his speed in the experimental Auto Union racer during Nürburgring tests nearly matched Hans Stuck’s lap times, Rosenberger’s competition license was denied by Nazi officials. Since the purpose of the state-backed Auto Union and Mercedes-Benz racing programs was to demonstrate Aryan superiority, Jewish drivers were prohibited.
Rosenberger wisely departed Germany to represent Porsche interests first in France, then in Switzerland. Upon his return in the summer of 1935, he was arrested by the Gestapo and dispatched to a concentration camp for “racial disgrace”—defined as relations with an Aryan woman.
Thanks to the intervention of his ally Veyder-Malberg, Rosenberger was released after but four days of internment; the Reich billed him 953 RM (about $230) to cover the cost of his “protective custody” and legal fees. Taking the beatings he suffered during confinement seriously, Rosenberger relocated to France and changed his first name to Alfred. Then in 1938, he moved to America, settling first in New York before seeking employment in Detroit.
With World War II raging, the U.S. government considered Rosenberger an enemy alien and restricted his movements. Because of that status, no car company would have him, so he moved to Los Angeles, changed his name again to Alan Arthur Robert, and opened a gas station. When that venture didn’t pan out, he worked as a day laborer, selling plastic products on the side. He finally obtained U.S. citizenship in 1944.
Robert’s fortunes improved in 1950 after he married Anne Metzger, formerly a secretary at the Porsche design office. The couple founded Roberts of California, which produced and sold high-end home decorations. They purchased a comfortable residence in Beverly Hills and helped Robert’s mother and sister immigrate to America. The intrepid car enthusiast also opened a shop called Coach Craft that specialized in custom bodywork and exhaust systems.

Rosenberger’s attempts to maintain a dialogue with Porsche and to obtain redress for his investments were fruitless during and immediately after World War II. While his salary continued when he represented Porsche in France, once he departed for America in 1938, payments and communications ceased under Nazi orders. The Reich seized his real-estate holdings in Pforzheim.
Following the hostilities, Ferdinand and Ferry Porsche and Anton Piëch were arrested in France for Nazi collaboration. Upon their release, economic conditions in Germany were so harsh that letters were dispatched to Rosenberger requesting cash, chocolate, and coffee care packages. That desperation was short-lived. The Volkswagen plant was soon up and running, yielding 46,000 cars in 1949 and a $1.25 per car royalty to Porsche for designing the Beetle. Company assets quickly rebounded to more than a million DM ($240,000 then, $3.5 million today), and production of Porsche 356s began.
Rosenberger sued Porsche for 200,000 DM (about $480,000 today) through the German retribution tribunal. When the dust finally settled in 1950, his award was one-fourth that amount plus his choice of a new Beetle or a 356. While the historical record doesn’t show why Rosenberger chose the Volkswagen, it should be assumed that what he sought was respect, the one thing no one at Porsche seemed willing or able to provide.
Don Sherman has been an automotive journalist for decades, contributing to numerous publications, including Car and Driver, Road & Track, Hagerty, and more.