Facing the growing competition in the globalized economy, Japan’s private sector has been looking out for human resources that can fill in the managerial positions of international branches. In response to this demand, policymakers conceived of the idea of Global Human Resources and launched several initiatives to internationalize education. Among these initiatives, this study focuses on the reform attempt to establish 200 International Baccalaureate (IB) schools. Interestingly, the cabinet led this initiative by forming complex relationship with the Ministry of Education (MoE), a traditional key actor in Japan’s education policy. Therefore, by studying the IB reform in Japan, this study intends to shed light on the interactions that occur within the government. Numerous studies have been conducted in the field of comparative education, exposing the changing relationship between public and private sectors or actors across different levels, such as international and local ones. However, scholars in the field have paid little attention to the complexity inside the government and how different actors within it interact and shape the policy process. Drawing on neo-institutional and organizational approaches, this dissertation examines the policy process of the IB reform through the three analytical units: institutions, ideas, and networks. In other words, it analyzes how different policy actors form networks and employ different ideas to promote their preferred modes of the reform under the institutional constraints that typically exist in the form of laws. To identify the aforementioned three elements relevant to the IB reform, I conducted a qualitative analysis by analyzing various kinds of documents, such as, policy reports, meeting transcripts, newspaper articles, and miscellaneous documents, which were either written by relevant policy actors or written for engaging them. In addition, I conducted 12 interviews with policy actors involved in the reform as members of policymaking bodies. To reduce the bias stemming from my positionality, I also held feedback sessions with three researchers in the relevant field. Finally, I performed a quantitative network analysis using lists of council members and identified which policy actor held strategically important positions. Through the analysis, I attempted to confirm the importance of key actors observed in the qualitative inquiry using the previously studied documents and conducted interviews. The study revealed how the interactions between the cabinet and the MoE arose from the changes in the three analytical units and influenced the consequence of the IB reform. Institutional changes in the policy process and education law enabled the cabinet to exercise greater influence on education since 2000. Particularly, the redefinition of the national curriculum as a minimum standard made it possible for the cabinet to introduce the IB, which did not align with the requirements of the national curriculum. Key policy actors emerged from both the cabinet and the MoE and formed a network to tap into the reconfiguration of institutional conditions, which led to the successful launch of the IB reform. However, the ideational gap between the cabinet and the MoE (particularly, its core segment, the Elementary and Secondary Education Bureau) persisted. While the former presented itself as a hub of novel ideas, intended to innovate education, and highlighted the need to raise talented students, the focus of the latter centered on maintaining the nation and increasing the standard of average or even low-achieving students. These normative differences were not easily reconcilable, and the network eventually broke into the two streams: the cabinet with the Association of National Universities and high-school stakeholders with the MoE (the Bureau). While the former introduced the IB as one mode of entrance exams, the former did not agree on using the IB as a tool for evaluating students’ thinking skills. This study contributes to the field of comparative education by presenting the analysis of the IB reform, in which novel actors emerged in education policy, that is, executives such as presidents and cabinets. Similar to private actors criticizing and attempting to intervene in public education, these executives intend to transform public education from within the public sector. More importantly, their primary interest is in producing elites. As shown in this study, the important task of educating the rest of the population may be assigned to the MoE, which suffers from financial shortage. If the executives coordinate with the business sector and concentrate resources on the select few, this division of work may threaten equity in public education.