Energy efficiency is the force behind economic growth that has a significant impact on the environment. This study investigated the impact of energy efficiency on ecological footprint by incorporating the environment Kuznets curve (EKC) model. Analysing data from G20 economies, the basic outcomes indicated that energy efficiency reduced ecological footprint and EKC is valid. Robustness test results validated the above conclusion. Institutional quality weakened the positive effect of energy efficiency on the environmental quality. Besides that, the mediation outcomes confirmed that energy efficiency leads to reduced fossil fuel consumption, thereby decreasing ecological pressure. When crossing the threshold value of the energy consumption structure, the parameter of energy efficiency underwent a transition from positive to negative. When the manufacturing proportion exceed a certain value, the influence of energy efficiency on ecological degradation was swift from negative to positive. By focusing on energy efficiency as an approach to address the ecological strain in the G20 economies, this research topic can serve as a springboard for policy conversations between researchers and governments. The study also proposed the following policy implications based on the findings: (1) governments should increase investments in energy efficiency improvement technologies; (2) policies should be strategically integrated to address a variety of concerns, including those related to the environment; and (3) energy and industrial structures should be upgraded to improve the environment.