The paper aims at contributing to the discussion about planning theory and participatory practices in the Global South by focusing on a planning experience for the Belo Horizonte Metropolitan Region, Minas Gerais State, Brazil, led by faculty, researchers and students at the Universidade Federal de Minas Gerais, between 2009 and 2019. The initiative unveils the University autonomy in designing and carrying out the metropolitan analyses and planning proposals, in adopting theoretical principles and methodologies and, in developing an outreach programme tightly linked to education and research, resulting in significant improvements in planning education, innovations in planning methodology and the potential for rooting radical planning practices in the metropolitan context. First, objects and subjects of the experience are introduced, together with the three phases of the process: the drafting of a metropolitan plan known as the Integrated Development Master Plan for the RMBH; the Metropolitan Macro-Zoning; and the review of municipal Master Plans within RMBH. Secondly, the trajectory and influences of Brazilian urban and metropolitan planning are reviewed to the extent that they fed into the experience. The discussion of municipal planning processes leads to an assessment of the experience’s main achievements. The concluding section offers some thoughts on rooting metropolitan and urban planning in critical theory and participatory practices, as a means to contribute to discussions of planning practices in the Global South.