The Big Mac became a major McDonald's branded product when it debuted in 1967.
The sandwich was created by Jim Delligatti, a McDonald's franchisee who operated restaurants in the Pittsburgh area. He developed a larger two-patty hamburger with a middle bun layer, helping the chain offer a more substantial menu item while retaining its familiar service system.
The product was first introduced in select markets before becoming nationally available in the United States in 1968. Its distinctive name, three-part bun, special sauce, and recognizable advertising made it more than a menu item: it became one of McDonald's strongest product brands.
The Big Mac is sometimes dated only to its national rollout, which explains why 1967 and 1968 both appear in historical references. The precise distinction is that 1967 marks the initial introduction, while 1968 marks nationwide U.S. availability.