Filet-O-Fish was created in 1962 as McDonald’s first fish sandwich.
Franchisee Lou Groen developed the sandwich for restaurants in predominantly Catholic neighborhoods, where many customers avoided meat on Fridays. The product gave McDonald’s a way to serve an important local customer group while extending the brand beyond beef hamburgers and fries.
The Filet-O-Fish became a nationally recognized menu name and remained part of McDonald’s permanent product identity. Its standard presentation has included a breaded fish fillet, a steamed bun, tartar sauce, and cheese, although details and fish species have varied by market and period.
Its history is often simplified into the claim that McDonald’s created a fish menu because of a general seafood trend. The more specific origin was Groen’s response to local Catholic demand and Friday sales. The sandwich’s branding value came from turning that regional business solution into a repeatable national product.