On May 15,1940, McDonald's Bar-B-Que restaurant opened in San Bernardino by brothers Richard (1909-1998) and Maurice (1902-1971) McDonald.¹ This was a time when the number of car owners was rising—there was a migration to the suburbs; drive-in restaurants were popular; and drivers would park and be served by female "carhops" in their vehicles. In 1948, the McDonald brothers revamped their successful restaurant, aiming to be more competitive.² They introduced a "Speedee Service System," a streamlined assembly line process that emphasized fast, consistent, and affordable food. They also limited and standardized menu options, reduced burger prices, and replaced carhop service with a walk-up, self-service model, creating a clean, comfortable environment that enhanced the customer experience. These innovations lead to the development of the modern fast-food restaurant model. The McDonald brothers sold this business model as part of their first franchised restaurant in Phoenix, AZ in 1952.³

In 1954, milkshake machine salesman Ray Kroc (1902–1984) visited a McDonald's restaurant that had ordered several multi-mixer machines from him.⁴ Kroc saw great potential in the McDonald's system and joined the company as a franchise agent. However, while Kroc envisioned nationwide expansion, the brothers were not as interested in rapid growth. In 1961, when there were around 300 restaurants in operation, the brothers agreed to sell the McDonald's name and concept to Kroc to franchise to other restaurant operators for $2.7 million.⁵ Today, McDonalds is one of the world's leading food service brands with more than 36,000 restaurants in over 100 countries.⁶ According to McDonald's, an estimated one out of every eight workers in the United States has experienced working at the restaurant.

Ray Kroc transformed the McDonald's business into this global fast-food empire by further revolutionizing it in several key ways. He expanded on the fast-food franchising model, offering opportunities for individual entrepreneurs to own and operate their own businesses under the brand. Franchise-level innovation was allowed to cater to local tastes. Kroc invested in marketing and advertising campaigns to build the brand. McDonald's traded common stock in over-the-counter markets starting in April 1965, and was listed on the New York Stock Exchange in 1966.⁷

The company has continued to innovate in the fast-food industry, introducing features such as drive-thru service, self-service kiosks, and mobile ordering, while its menu has evolved to meet changing consumer preferences and regional appetites. Recently, the chain has embraced sustainability initiatives, such as environmentally friendly packaging, reflecting its movement towards responsible business practices.⁸ McDonald's has also faced controversies, including concerns over its menu's impact on public health, as well as criticism for targeting low-income and Black neighborhoods, which some argue contributes to health disparities in these communities.⁹ Amid these challenges, however, McDonald's has also engaged in charitable efforts that contribute to its complicated legacy. Through initiatives like the Kroc Foundation, which funded medical research, and Ronald McDonald House Charities, providing support for families with hospitalized children, McDonald's has taken steps toward social responsibility. These efforts highlight the wide-ranging nature of the company's influence.