Lou Groen created the Filet-O-Fish, McDonald’s first non-hamburger sandwich, in 1962.
Groen was a McDonald’s franchisee in Cincinnati, Ohio, where many customers observed Catholic dietary practices that traditionally avoided meat on Fridays. He developed a fish sandwich to attract those customers during a period when sales could otherwise fall sharply.
The product was tested alongside a meatless alternative proposed by McDonald’s founder Ray Kroc. Groen’s fish sandwich performed better in the test and became part of the McDonald’s menu.
The Filet-O-Fish is often remembered only as a seasonal menu item, but its history illustrates how local customer needs influenced national branding. Its distinctive name and sandwich format also expanded McDonald’s identity beyond hamburgers.