Only in the last years, Sustainable Open Innovation has become a unique issue from the convergence between the concept of Open Innovation and sustainability as well as a challenge for the future business models of companies. Given that the aim to build a more sustainable world is one of the most relevant targets to reach over the world, the present work has focused on how Open Innovation is a catalyst for sustainability, by proposing a model for the case study in an underdeveloped sector, such as the energy one. Specifically, through the analysis of the ENEL case study, the relationship between Open Innovation (OI) and a strategic approach to CSR has emerged. The strategic approach to CSR, guided by open leadership aimed at involving stakeholders and creating shared value, creates an organizational culture and an environment favorable to the development of Open Innovation strategies; furthermore, the Open Innovation processes support the integration of the social, environmental, and economic objectives of companies. The findings show how Open Innovation can address sustainability practices and objectives. Through the application of the framework called SKiN, which provides a qualitative and replicable tool, the study allows to evaluate the organizational permeability as a critical success factor for both sustainability strategies and innovation.