Countries globally are grappling with challenges such as food insecurity, poverty, inequality, economic growth, and climate change. Education for sustainable development (ESD) is necessary for all nations to achieve Sustainable Development Goal (SDG) 4 and its targets. The purpose of this qualitative study was twofold. Firstly, to explore how Brazil and South Africa have implemented ESD towards the attainment of SDG 4. Secondly, to provide strategies to overcome classroom challenges and enhance the implementation of ESD towards the realisation of SDG 4. To address the research objectives of this study, qualitative document analysis, following the principles of grounded theory, was employed, grounded in a postmodern research paradigm. The findings indicate that for improved implementation, nurturing sustainability-related competencies of educators, educational leaders, and students through professional development and teacher training courses holds high potential to effectively respond to several challenges and to shift the world onto a sustainable path. The implications of this chapter suggest that, if SDG 4 is to be realised by 2030, Brazilian and South African governments and educational leaders should further improve enrolment rates (at all levels of education), address budget cuts, and tackle inequalities and disparities that continue to manifest in the respective education systems.