This article deals with Pierre Rosanvallon's intellectual profile. One of the most important French historians, Rosanvallon has recently entered the "Collège de France" where he holds the chair of "History of politics". The article charts the main steps of his intellectual production dating back to 1969 when he started working at the Cfdt trade union as head of the economic analysis bureau. His union activism, his theories about self-management and the necessity of redesigning the welfare state are the building blocks of his subsequent historical production and of his monumental history of French democracy. The essay seeks to point out the continuity between his "political" experience and the "academic" one, emphasizing that "it is a nonsense to distinguish between 'vita activa' and 'vita contemplativa'".