In his inaugural lecture at the Collège de France, he expounded the originality of his approach, which is to consider the history of democracy as the exploration of a problematic experience. Democracy, he posited, establishes politics as a field that constitutively resists closure by virtue of the tensions and uncertainties that underpin it. "As it forms the basis for an experience of freedom, the history of democracy, he noted, is therefore not simply a history of frustrations or betrayed utopias: it has become a deeply intertwined history of disenchantment and indeterminacy." This approach of politics has led Pierre Rosanvallon to consider the historical factor as an essential condition to fully grasp it. His ambition has been to envision democracy by following the thread of its history. He further states that it is not enough merely to say that democracy has a history, but that one must take the more radical step of recognizing that it is a history. History is an active laboratory of our present and not simply its background. He outlined the principles of this approach in Pour une histoire conceptuelle du politique (2003).

This approach to considering history as the substance of a political theory helps to understand how Pierre Rosanvallon connects his academic work with constant attention to the urgent issues of today. Beyond his work as a writer, he has never ceased to increase his involvement in the life of the polis in a bid to shed light on current affairs through input from the social sciences. From 1982 to 1999, he chaired the Saint-Simon Foundation, a reformist think-tank whose many publications left their mark. In 2002, he launched La République des Idées, an eponymous collection published by Editions du Seuil, and regularly organizes large-scale forums for the general public. He has also launched a website - laviedesidees.fr - which is more directly connected to his chair at the Collège de France, and is a journal of news and analysis dedicated to ideas and intellectual production in France and abroad.

Pierre Rosanvallon's work has been translated into 22 languages and published in 26 countries. Alongside his teaching commitments in France, he also gives lectures and conferences in academic institutions all over the world.