How do the processes of national coordination of public policies influence the implementation of educational policies that transit between different levels of government in the Brazilian political system? In order to answer this research question, we selected as the object of study a recent Brazilian educational policy that raised a number of conflicts during its formulation. It is the High School Reform (also called New High School), which was formulated and enacted by Provisional Measure in 2016, and has been designed and implemented since then, passing through different governments between 2016 and 2022. In this sense, the general objective of the research can be described as that of understanding how the processes of national coordination of public policies influenced the implementation of the High School Reform, considering that the formulation and implementation were carried out by different levels of government. To achieve the general objective, the research proposes to: describe the contexts of the federal and state education subsystems prior to the implementation of the New High School; analyze how the process of implementing the New High School in the country took place, focusing on understanding the national coordination of the policy; analyze the process of implementing the New High School in two selected states, in order to understand the possibilities of affecting the previous contexts and the national coordination. The research is mixed in nature. The use of qualitative data, collected through clipping, documentary research, and structured interviews is complemented by the use of quantitative data, and the quali-quanti dimensions are articulated based on the strategy of content analysis. The theoretical framework mobilized for the study comes from the field of political science and was built through the articulation of references that deal with: political system and policy subsystem; policy implementation contexts; actors; and public policy instruments, for the understanding of the configuration of the political system and the education policy subsystem, the main focus of this Thesis. The analyses carried out indicate that the Brazilian federative structure and the different contexts that marked the political system and the subsystem of education policies in the country promoted a series of challenges and difficulties for a consolidated implementation of the New High School by all the states. Different contexts took shape during the implementation process, which began in 2017 and is still under development today (2022). The role of non-state actors was essential for the federal coordination of the implementation. However, several factors have determined partial and regionalized successes in the policy implementation process. These factors are: the fading role of the Ministry of Education in the federative conduct of the policy, the crises and emergency demands caused by the pandemic, and the heterogeneity of previous experiences and state capacities among the states.