Given that corporate leaders seek to ensure the long-term sustainability of their organization, this study explores how a business adopting a Thai Sufficiency Economy philosophy improves its sustainability performance. Adopting the Sufficiency Thinking model as the research framework, this study uses a qualitative research approach with a set of different data collection techniques to explore a sample Small–Medium-sized Enterprise (SME) called Plan Creation. Collected data are identified as themes, according to the Sufficiency Thinking model. Our findings reveal that there is a close fit between the collected data and the Sufficiency Thinking model. Virtuous attributes, individual and shared knowledge and the decision-making framework of Sufficiency Mindset are observed through the sustainable leadership actions, leading to, among other things, social and environmental innovation. Implications for practicing managers and directions for future research are also discussed