Greek family firms developed sustainable businesses in the Azov Sea area during the nineteenth century. Despite the discouraging conditions for entrepreneurship and the geographical constraints, they succeeded in constructing trading and shipping networks based on kinship, common historical experience, and close links with their place of origin. Medium-size firms represent the main bulk of Greek family enterprises that were located in the Azov port cities, and through their activities these contributed to the integration of the area's economy in the world market. Geographical mobility and diversification in transport services were their main responses to situations of high risk and controversy. The key to understanding their resilience and flexibility in adapting to environmental changes resided in their family culture, shared values, and social-network support that added value to their international performance.