Islamic education in the Indonesian Archipelago has developed through pesantren as institutions that play a significant role in the transmission of knowledge, character formation, and the strengthening of social values. KH. Hasyim Asy'ari made a major contribution through his educational thought, which was implemented at Pesantren Tebuireng since 1899. This study aims to examine the historical background of KH. Hasyim Asy'ari's educational thought, analyze its educational concepts, and explain its implementation and contribution to the development of Islamic education in the Indonesian Archipelago through Pesantren Tebuireng during the period 1899–1947. This study employed a qualitative approach using the historical research method, including the stages of heuristics, source criticism, interpretation, and historiography. The data were collected from the works of KH. Hasyim Asy'ari, historical documents, pesantren archives, and relevant scholarly literature. The findings reveal that his educational thought emphasizes knowledge, adab (ethical conduct), morality, and social responsibility as the fundamental pillars of human development. Pesantren Tebuireng served as the practical arena for implementing these ideas by integrating the Islamic scholarly tradition, character education, curriculum development, and adaptation to social change. The study concludes that KH. Hasyim Asy'ari's educational thought made a substantial contribution to the development of Islamic education in Indonesia through educational practices that integrated Islamic values, culture, and nationalism. The novelty of this study lies in its historical analysis linking KH. Hasyim Asy'ari's educational thought with the institutional practices of Pesantren Tebuireng as a model for the transformation of Islamic education in the Indonesian Archipelago.