The present study develops a sustainable social enterprise model and examines relationships between corporate sustainability practices and sustainability performance outputs in a social healthcare enterprise in Thailand. Findings reveal four predictors of corporate sustainability, including Leadership, Stakeholder Focus, Resilience Development, and Sharing practices. All of them have direct and/or indirect positive effects on corporate sustainability performance outputs as measured by brand equity, socioeconomic performance and environmental performance. The study also proposes a coherent theory of Sufficiency Economy in business, build upon key theories from relevant fields. Lastly, the present study provides future research directions and managerial implications based upon the model.