This paper contributes to research on the growing expectation of hospitality businesses to implement sustainability strategies. By using the theoretical framework of professional knowledge cultures, as discussed by Nerland [Nerland, M. (2012). Professions as knowledge cultures. In Professional learning in the knowledge society (pp. 27–48). Brill/Sense], together with concepts of leadership and management, the study presents a novel approach. The aim is to explore the knowledge culture and the processes of learning and leadership formation in the restaurant industry to understand how these impact sustainable decision-making in restaurants. Through a narrative method, a typical industry career is illuminated, which mirrors the route to becoming a leader while adopting sustainability strategies. One podcast interview was used as research material to introduce a new data source derived from social media. The sampling considers the relevance of the narrators’ knowledge and experience of the chef's profession and is therefore representative of a naturally occurring data. The analysis, based on knowledge culture, leadership practices, and sustainability, shows that the size of the restaurant matters for financial and socially sustainable decision-making. This is explained by the production flow in large organizations, which depends on calculated and effective work methods. Environmental sustainability strategies appear as a personal concern and are thereafter transformed into the knowledge culture, identified as a normative leadership.