Longevity is at the core of what makes family businesses special. Unlike most attempts to explain longevity that have focused primarily on the factors within a family business that lead to longevity or the factors outside of an organization’s environment, we adopt a business-history perspective that enables us to show how the interplay between the organization and its environment can help to explain family business longevity. Building on the category literature, we trace the interaction of a small Swedish fourth-generation high-quality furniture manufacturer with its category over a period of more than 120 years. We identify the internal mechanisms driving family business longevity, the external mechanisms driving category development as well as the mechanisms underlying their interaction. Specifically, we provide new insights into how agency exercised by the family business contributes to the shaping of the category they are a member of, thereby nurturing their business longevity.