On May 15, 1955, Ray Kroc opened the first McDonald’s restaurant under his franchising company at 400 Lee Street in Des Plaines, Illinois. The site is widely recognized as the first restaurant opened and operated by Kroc’s McDonald’s Systems, Inc., which later became the McDonald’s Corporation. The store’s opening formalized a business model that combined a standardized, limited menu, assembly-line food preparation, and rapid service—elements developed by brothers Richard and Maurice McDonald in San Bernardino, California, during the 1940s and early 1950s. Ray Kroc, a Multimixer milkshake machine salesman who encountered the McDonald brothers’ efficient operation in 1954, proposed expanding their system through franchising. The brothers had operated several restaurants and had experimented with streamlining their kitchen to emphasize burgers, fries, and shakes. Kroc saw national potential in the uniformity and speed of their method. In 1955 he established McDonald’s Systems, Inc., signed franchising agreements, and opened the Des Plaines location as the first restaurant under his franchising leadership. The Des Plaines site embodied the standardized approach Kroc promoted: simplified menu choices, cash-and-carry counter service, strict kitchen procedures, and a focus on consistency across locations. These practices aimed to ensure customers received the same product and experience regardless of location, a central tenet of franchising that allowed rapid geographic expansion. Under Kroc’s leadership, franchise sales materials, training programs, and operational manuals were developed to replicate the system. Historical accounts note that the Des Plaines restaurant differed from the McDonald brothers’ original San Bernardino location in ownership and management: the Des Plaines store was operated by Kroc and his franchisees under contracts with McDonald’s Systems, while the brothers retained ownership of their original business for several years. The relationship between Kroc and the McDonald brothers evolved into legal and financial disputes over control of the name, real estate, and the company’s direction—matters that are well documented and sometimes disputed in detail by different sources. The 1955 opening is significant for the history of American fast food and franchising. It marks the moment when the McDonald’s concept shifted from a local, innovative restaurant experiment to a franchised, corporately organized enterprise that would expand rapidly across the United States and internationally in subsequent decades. The practices established in this period—uniformity, centralized purchasing, brand standards, and franchisor oversight—became defining features of modern fast-food chains. The Des Plaines building itself became a point of public interest and was later replaced by a replica museum and converted site that acknowledges the location’s role in McDonald’s corporate history. Historians and industry analysts use the event to illustrate mid-20th-century changes in American consumer culture, postwar suburban growth, and the rise of franchising as a business model. While the broader cultural and economic impacts of McDonald’s expansion are subject to extensive analysis and debate, the May 15, 1955 opening remains a clear milestone in the company’s chronology. Sources for this event include contemporary news coverage, corporate records, and later historical studies of McDonald’s business development. Some details—such as the precise nature of early contractual arrangements and the timeline of ownership transitions between Kroc and the McDonald brothers—are treated differently in various accounts; where disputes exist, historians rely on primary documents, court records, and corporate archives to clarify specifics.