O dd Reitan is a Norwegian billionaire and the founder of the Reitan Group, a vast retail and real estate empire. His entrepreneurial journey began in his hometown of Trondheim, where his parents ran a small grocery store. Inspired by their work, Reitan opened his first store in 1972. He developed a keen interest in discount retail models he observed abroad and, in 1979, he founded the REMA 1000 chain of discount grocery stores. The name stood for 'Reitan Mat' (Reitan Food), and the '1000' initially referred to its goal of stocking 1,000 different items.

The REMA 1000 concept, based on a franchise model and a focus on low prices and efficiency, was a phenomenal success. The chain expanded rapidly throughout Norway and then into other Scandinavian countries like Denmark. Over the decades, Reitan diversified his business interests under the umbrella of the Reitan Group. The group now includes the convenience store chains Narvesen in Norway and Pressbyrån in Sweden, as well as significant holdings in real estate and energy through subsidiaries like Reitan Eiendom and Uno-X. The company remains family-owned, with his sons Ole Robert and Magnus holding key leadership positions.