In McDonald's branding history, the first nationally introduced breakfast sandwich was the Egg McMuffin.
Herb Peterson created the Egg McMuffin in 1971 at a McDonald's restaurant in Santa Barbara, California. The sandwich used an English muffin, a round egg, Canadian bacon, and cheese, giving McDonald's a portable breakfast item with a distinctive product identity.
McDonald's introduced the Egg McMuffin nationally in 1975. Its success helped establish breakfast as a major part of the chain's daily business and created a durable brand name that remains closely associated with McDonald's.
The Egg McMuffin is sometimes confused with later breakfast products. The Sausage McMuffin followed as a variation, while the McGriddle was introduced decades later. The Big Breakfast is a plated breakfast meal rather than the original McDonald's breakfast sandwich.