McDonald is the surname of brothers Richard and Maurice McDonald, whose restaurant became McDonald's.
Richard and Maurice McDonald opened a drive-in restaurant in San Bernardino, California, in 1940. They later reorganized the business around a simplified, assembly-line-style method of preparing a limited menu. That approach became the foundation of the Speedee Service System and the later McDonald's brand.
The company name refers to the brothers' family name, not to Ray Kroc. Kroc was the businessman who became involved in the franchise operation in the 1950s and played a major role in expanding McDonald's into a global chain. He did not supply the surname used in the brand name.
The name also predates the Golden Arches, Ronald McDonald, and modern global advertising. Those later branding elements built recognition around a restaurant identity that began with the McDonald brothers' name and service model.