The McDonald brothers adopted the name McDonald's when they reopened their restaurant in 1948.
Richard and Maurice McDonald first opened a drive-in restaurant in San Bernardino, California, in 1940. It was known as McDonald's Bar-B-Q and served a broader barbecue-oriented menu. In 1948, the brothers temporarily closed and reorganized the business around a smaller menu and faster counter service.
The reopened restaurant used the McDonald's name and introduced the Speedee Service System. This operating model emphasized standardized preparation, limited choices, and rapid service, laying important foundations for the chain's later visual and commercial identity.
The 1948 reopening is not the same event as Ray Kroc's involvement, which came later, or the opening of the first franchised McDonald's restaurant. The name change and service redesign came from the McDonald brothers and preceded the company's large-scale expansion.