This study critically examines the OECD's concept of 'student agency', which has recently spread to policy discourse, and is narrowly utilized as 'agency', 'self-directed learning', and 'counter-concept to teacher-directed learning', through the theoretical discussion of agency, and then examines how student agency is constructed in the actual school context, and what are the forms and conditions of schooling in which student agency is manifested, through the case of 'Between-in' High School, a futuristic Hyuk sin school. The results showed that agency has been discussed for a long time in philosophy and social sciences, but scholars have had different perspectives and emphases on the concept. In particular, it is a complex and dynamic concept that cannot be encompassed by the translation 'student initiative'. Moreover, the recent neoliberal framing of agency as an autonomous and flexible self-entrepreneurial identity adds to the dilemma of addressing the concept of agency in education. Therefore, given that the OECD, as a key actor in global education governance, has long been committed to the formation of a new human capital by emphasizing the neoliberal economic order, it is necessary to critically engage with educational discourses, data, and visualizations produced in various ways. Furthermore, the misuse of concepts by the state to conveniently excerpt educational discourse produced by various units to serve as a basis for educational policy is a matter of concern beyond uncritical borrowing. The results of the study showed that student agency at 'Between-in' High School, Hyuk sin school, consisted of autonomy and resistance, community and relationships , and reflection and critical thinking . To this end, the school strengthened student autonomy by emphasizing the sharing of educational philosophy, the formation of a communal culture of teachers, and the practice of curriculum and instruction. The teachers and students at 'Between-in' High School, understood the complexity and contextuality of agency and multidimensionally constructed it. Therefore, rather than stipulating and policing teachers and students as objects of change and innovation, we should listen to the existential life context of teachers and students in the educational field, what factors promote or hinder the expression of their agency, and meaningfully analyze and reflect their practical experiences into policy.