The purpose of this paper is to study the role of individual agency in the process of institutional change. We conducted a historical study to explore the motivations and activities of two prominent individuals in business and politics before, during, and after the Finnish Civil War. Our most important finding is that the improvised actions of individuals with complex interests were causally related to long-term institutional changes. Specifically, our study contributes to theory development in the field of institutional analysis by showing how individual actors can be a mechanism for both institutional continuity and change. On the practical side, our account can help managers understand the power of improvised activities in the face of ambiguity and uncertainty, especially if there is the possibility of acting in concert.