The name “Big Mac” became a major part of McDonald's branding after the sandwich was introduced in 1967.
The Big Mac was created by Jim Delligatti, one of McDonald's franchisees, and first sold in the United States in 1967. It became nationally available in 1968. Its distinctive three-part bun, two beef patties, special sauce, lettuce, cheese, pickles, and onions gave McDonald's a flagship product that could be promoted by name.
The product's branding became especially powerful because “Big Mac” was short, memorable, and easy to use in advertising. The sandwich later became associated with the Big Mac Index, an informal economic comparison created by The Economist in 1986.
A common mix-up is to treat 1967 and 1968 as competing launch dates. The sandwich debuted regionally in 1967 and reached nationwide U.S. availability in 1968, so both dates appear in historical accounts for different stages of its rollout.