Lijphart’s (1999, 2012) ground-breaking distinction indexes between consensus and majoritarian democracies (based on 10 features of democracy) represents the influential and prominent typology of modern democracies. On the other hand, sustainable development can be defined as development that meets the needs of the present without compromising the ability of future generations to meet their own needs. However, the previous literature is not clear about the performance of different democratic structures on various environmental sustainability standards. With the purpose of exploring the effects of patterns of majoritarian and consensus democracy on environmental sustainability, this study selected the independent variables of “executives-parties” and “federal-unitary”, and the dependent variables of environmental health, ecosystem vitality and environmental performance index. Panel data modeling was used to analyze the secondary data for OECD and/or EU-member countries for the period of 2000 to 2020. Several results emerge from this study. First, the possibility to promote environmental health from the majority system along the “federal-unitary” dimension of governmental organization and the consensus system along the “executives-parties” dimension of democratic representation. Second, the possibility to promote ecosystem vitality from the consensus system along the “federal-unitary” dimension. Third, the possibility to promote environmental sustainability from the consensus system along the “federal-unitary” dimension. In sum, the results from this study indicate that in the most advanced and wealthiest countries, the individual and total performances on environmental sustainability of consensus democracy are superior to majoritarian democracy. Besides, the effects on environmental sustainability of shared and limited power in governmental organizations are superior to comprehensiveness of democratic representation in executive and legislative sectors.