The active school and the New Education are identity symbols of the pedagogical reform movements in the first third of the twentieth century. Adolphe Ferrière was a tireless apostle of this pedagogical cause, especially during the decade of 1920-30, “the pedagogical period” of his biography. At the same time, Rousseau’s thought was in the basis which the renewal’s principles were constructed. “Tout d’abord Jean-Jacques”, Ferrière wrote in the Journal of Genève (1923). The Swiss Pedagogue regards Rousseau as the pioneers’ precursor (Trois pionniers de l’Éducation Nouvelle, 1928) and devotes him special attention in the first edition of L’école active (1922). This paper proposes a new reading and interpretation about Ferrière’s essays and conferences. From the pedagogical hermeneutics perspective and some elements of the conceptual history, we propose to analyse and critique the presence of Rousseau’s naturalism and thought in the principles of the active school and the New Education. With the same pretext and objective we will also approach, through Ferrière, to the influence of these principles in the basis of the Catalan pedagogical renewal in the first third of the twentieth century.