This history thesis tells the story of a pioneer: architect, visionary and inventor Jón Kristinsson (Reykjavík, 1936). He is a well-known figure within the Dutch context for his integral approach to architecture and his perseverance in pursuing his ambitions for his designs from the late 1960s until the early 2010s. The following research question is addressed: What was the role of Jón Kristinsson in the development of minimum-energy building design in the Netherlands?. In the first chapter, a brief history of sustainability is given, historically grounding the thesis through overview literature by architects and professors Djalali & Vollaard (2008), Loorbach (2024) and Steele (2005). It becomes clear that Kristinsson does not stand alone, pioneering his own approach while following new ideologies. In chapter two, the history of minimum-energy building in the Netherlands, as written by scholars Van Hal & De Vries (2000), Zeiler (2013), Melet (1999) and Kristinsson himself, is combined with the history of Kristinsson through primary sources and case studies. Kristinsson develops his integral design approach early on, while Dutch policies follow international crises at first. Only from the 1990s, after a time of experimentation, a programmatic approach was applied nationally, characterized by non-compulsion and rational norms. It is evident that Kristinsson played various roles, both as an architect and a teacher. As a pioneer, he contributed not only to the physical development of minimum-energy buildings, but also to the development of an ideology that is integrated sustainable design. These are the kind of stories we need to tell, to continue working towards a sustainable future today.