The interdependence between the economy and the environment necessitates integrated policymaking that recognizes the biological limits of our world and the scarcity of these natural resources. At the 1992 Earth Summit, countries agreed to adopt a National Sustainable Development Strategy (NSDS) which should comprise the integration of economic, social, and environmental policies across sectors, territories, and generations; country ownership and commitment; broad participation and effective partnerships; development of the necessary capacity and enabling environment; and focus on outcomes and implementation. Working from these key factors and based on decades of international research and peer reviews of these policies, this study hypothesizes four relationships to test the influence of these principles on the successful execution of an NSDS. Offering the first formal framework which theorizes and evaluates connections between these dimensions, this qualitative approach is applied to two case studies, South Africa and Germany, by the use of documentary analysis and semi-structured interviews. The present study finds that embedding NSDS programs and institutions within existing policy agendas and organizations is extremely difficult, especially in countries with a solid history of environmental policy. Also, the significant role of subnational governments and entities in all aspects of policymaking must be taken into account for the effective implementation of a National Strategy. The present research examines the necessity of specific policymaking processes and implementation mechanisms for an effective National Sustainable Development Strategy, ascertains common implementation challenges, and offers recommendations for the improved implementation of National Sustainable Development Strategies.