There, through his father's connections, Schmidl, the Austro-Hungarian Consul in Morocco, requested his services, getting Jellinek diplomatic posts at Tangier and Tetouan, successively.
He resumed his diplomatic career as Austrian vice-consul at Oran, Algeria, and also began trading Algerian tobacco to Europeans, in partnership with Rachel's father.
He also worked as an inspector for the French Aigle insurance company and traveled to Vienna briefly in 1881 at the age of 28 to open one of its branch offices.
Two years later, in 1884, Jellinek joined the insurance company full-time and moved with the family to Baden bei Wien, Austria, where they lived in the house of a wine dealer named Hanni.
Helped by his diplomatic career, he became the Austrian Consul General in Nice, and began selling automobiles, mainly French makes, to European aristocrats spending winter vacations in the region.
Associated with the automobile business were Leon Desjoyeaux, from Nice, and Alsatian cyclist Karl Lehmann, who acquired the sole French agency and adopted the alias of "C. L.
It was in Nice that Jellinek became enthralled by the automobile, studying any information that he could gather about it and purchasing successively: a De Dion-Bouton, a Léon-Bollée Voiturette, both three-wheelers, and a four-seat Benz motorized-coach.
In 1899 he married Madelaine Henriette Engler (Anaise Jellinek), and had four more children: Alain Didier, Guy, Rene and Andree (Maya).
Seeing an advertisement for a DMG car in the weekly magazine Fliegende Blätter, Jellinek, now aged 43, travelled to Cannstatt, (near Stuttgart), in 1896, to find out more about the company, its factory, and the designers Gottlieb Daimler and Wilhelm Maybach.
Among French car-makers such as Peugeot, Panhard & Levassor and other makers licensed to sell Daimler-engined vehicles in France there was a shortage of cars, and Jellinek benefited by being able to beat other suppliers' lengthy waiting-times.
Jellinek kept contacting DMG's designers with his ideas, some were good, but often with harangues, such as "Your manure wagon has just broken down on schedule"; "Your car is the chrysalis and I want the butterfly"; and "Your engineers should be locked up in an insane asylum.
On March 30, 1900, Wilhelm Bauer decided spontaneously to enter the Nice-La Turbie hill climb but crashed fatally after hitting a rock on the first turn while avoiding spectators.
Nonetheless, Jellinek came to an agreement with DMG on April 2, 1900, by promising the large sum of 550,000 Goldmark if Wilhelm Maybach would design a revolutionary sports car for him, to be called the Mercedes great right, of which 36 units had to be delivered before October 15.
Jellinek also became a member of DMG's Board of Management and obtained the exclusive dealership for the new Mercedes for France, Austria, Hungary, Belgium and United States of America.
He itemized many new parameters to overcome the problems found in many of the ill-designed "horseless carriages" of the time which made them unsuitable for high speeds and at risk of overturning: The model would be officially called the Daimler-Mercedes which the DMG chairman accepted readily as it overcame the problem of the Daimler name in France being owned by Panhard & Levassor.
The director of the French Automobile Club, Paul Meyan, stated: "We have entered the Mercedes era", a sentiment echoed by newspapers worldwide.
DMG's sales shot up, filling its Stuttgart plant to full capacity and consolidating its future as a car making company.
He also became disillusioned by DMG's technical department which he called "those donkeys" and built his own large repair facilities at Nice behind Villa Mercedes.
In 1909 when in Monte Carlo, Jellinek finally severed his commercial activities to concentrate on his consular work but did purchase some casinos in the region.
A decade after his death, in 1926, amid the German post-war crisis, DMG merged with Benz to become the Daimler-Benz company with their automobiles called Mercedes-Benz.