The Big Mac was created by Jim Delligatti, an early Ray Kroc franchisee who was operating several restaurants in the Pittsburgh area. It was invented in the kitchen of Delligatti's first McDonald's franchise, located on McKnight Road in suburban Ross Township. The Big Mac had two previous names, both of which failed in the marketplace: the Aristocrat, which consumers found difficult to pronounce and understand, and Blue Ribbon Burger. The third name, Big Mac, was created by Esther Glickstein Rose, a 21-year-old advertising secretary who worked at McDonald’s corporate headquarters in Oak Brook, Illinois.[3] The Big Mac debuted at Delligatti's Uniontown, Pennsylvania restaurant in 1967, selling for 45 cents. It was designed to compete with Big Boy restaurants' Big Boy sandwich; Eat'n Park was the Pittsburgh area's Big Boy franchisee at the time.[5] The Big Mac proved popular, and it was added to the menu of all U.S. restaurants in 1968.

The Big Mac consists of two 1.6 oz (45.4 g) (0.0454 kg) beef patties, "special sauce" (a variant of Thousand Island dressing), iceberg lettuce, American cheese, pickles, and onions, served in a three-part sesame seed bun.The Big Mac is known worldwide and is often used as a symbol of American capitalism. The Economist has used it as a reference point for comparing the cost of living in different countries – the Big Mac Index – as it is so widely available and is comparable across markets. This index is sometimes referred to as Burgernomics.The name was popularized by a 1974 advertising campaign featuring a list of the ingredients in a Big Mac: "Two all-beef patties, special sauce, lettuce, cheese, pickles, onions – on a sesame seed bun."[8]

Big Mac Sauce is delivered to McDonald's restaurants in sealed canisters designed by Sealright, from which it is meant to be directly dispensed using a special calibrated "sauce gun" that dispenses a specified amount of the sauce for each pull of the trigger.[9] Its design is similar to a caulking gun.

In 2012, McDonald's admitted that "the special sauce ingredients were not really a secret" because the recipe had been available online "for years".It consists of store-bought mayonnaise, sweet pickle relish and yellow mustard whisked together with vinegar, garlic powder, onion powder and paprika.

The Big Mac, along with many other McDonald's products, was first served in a "clamshell" styrofoam container that was phased out beginning in 1990 due to environmental concerns. The product is now sold in a collapsible cardboard box.