Yes folks, it all started back in 1918 when 22-year old Walter L. Jacobs opened the first car rental business in Chicago with a fleet of 12 Model T Fords. Five years later, Jacobs sells the company to John Hertz, head of the Yellow Cab and Yellow Truck Company, and the company name and iconic black and yellow logo are on their way to being one of the most recognizable brands on the planet.
This ad from 1959 talks about the "Hertz Habit" and their "U-Drive It" a.k.a. ("Drive-Ur-Self") system. Pretty hokey names, but hey, they were pioneering an industry. The idea of being able to rent a car, something we take for granted today, was completely foreign back when they started out.
Interestingly, in the earliest years, rental car companies became associated with criminal activity, especially during Prohibition. Many believed that cars were often used by bootleggers, bank robbers and prostitutes. After the 18th Amendment was repealed in 1933, the industry was able to regain a respectable reputation, and the business grew.
Kind of puts the whole "Hertz Habit" moniker in a whole new light.