This article proposes an alternative developmental framework that synergizes the roles of both the state and Civil Society Organizations (CSOs) to achieve sustainable socio-economic development in Isiolo County. The guiding research question was: What kind of developmental model can enhance the partnership between the state and CSOs for sustainable socioeconomic progress in Isiolo County? Challenging the neoliberal and donor-driven notion that non-state actors alone can drive socioeconomic development, this article asserts that the state's role remains crucial. Using the developmental state theory to analyze findings and a descriptive design for its methodology, data were gathered from both primary and secondary sources through snowball and purposive non-probability sampling techniques. The results reveal that CSOs working independently are insufficient for achieving sustainable socioeconomic development without the state's regulatory and coordinating involvement. Moreover, existing complementarity strategies, where the state and CSOs pursue similar objectives with different approaches, have not been successful. This paper advocates for a collaborative state-CSO approach, where both entities share aligned goals and methods to effectively drive socioeconomic transformation in Isiolo County.