Abstract: As a world-renowned critical and reflective historian of librarianship, Wayne A. Wiegand has reconstructed the historical narrative of American public libraries and their professional systems through his unique theoretical perspective. This paper systematically reviews his representative works, conducts a detailed analysis of core texts, and distills Wiegand's key arguments on the American library profession. It then compares and analyzes his ideas with Michel Foucault's “knowledge-power-discourse” theoretical framework. The study finds that Wiegand's critical practice was deeply influenced by Foucault's philosophy. His reflections focused on public libraries and their professional systems as institutionalized domains where power and discourse operated implicitly. He systematically revealed the cultural disciplining and social reproduction functions embedded within these domains. This critical approach not only challenges conventional understandings of the democratic role and professional neutrality of libraries but also demonstrates the explanatory power and theoretical productivity of philosophical theory in the field of library history research. Wiegand's research has had a profound impact on the American library community and provides important insights for the development of library services and theoretical research in other countries and regions around the world. For China's library community, Wiegand's research not only stimulates reflective self-awareness among disciplinary actors but also demonstrates how philosophical insights can be transformed into disciplinary reflective capacity. As China's library science advances towards the strategic goal of constructing an autonomous knowledge system, employing the practical functions of philosophical criticism to maintain reflection on institutional structures, technologies, and discursive power may help strengthen the theoretical foundations of an autonomous knowledge system for the discipline.