From the perspective of institutional economics, we investigate the impact of fiscal decentralization on regional green development in China and its transmission mechanism through influencing sports fiscal expenditures on regional green development. Based on panel data of Chinese provincial regions from 2006 to 2017 in China, we use fixed effects models, two-stage least squares, and mediating effects models to find that fiscal decentralization accelerates regional green sustainability. Fiscal decentralization can enhance the government’s emphasis on sports and promote the smart and intelligent development of the sports and health industry, thus contributing to the improvement of green and sustainable development. There is regional heterogeneity in the effect of the governmental emphasis on sports, and the mediating effect of the degree of emphasis on sports is more obvious in the eastern region. We verify the possibility that the government can accelerate economic green sustainability by raising the importance of the sports and health industry development and promoting the intelligent infrastructure of sports and enrich the theoretical study of the ecological effect of fiscal decentralization from the perspective of sports economic development.