The McDonald brothers converted their San Bernardino restaurant to a self-service fast-food model in 1948.
After operating a conventional drive-in, Maurice and Richard McDonald closed the business for several months and redesigned it. They cut the menu substantially, removed carhop service, introduced walk-up ordering, and organized the kitchen for speed and consistency.
This change was central to McDonald's branding history because it made the restaurant's identity about a repeatable system, not just a family name or a local menu. The brothers promoted the approach as the Speedee Service System, using a stylized chef mascot named Speedee in early branding.
The year is often confused with 1940, when the first McDonald's restaurant opened, or 1955, when Ray Kroc opened his first franchised McDonald's. The decisive fast-food redesign happened between those milestones, in 1948.