Ensuring a green supply of critical metals is essential to achieve high-quality economic development and ecological security. Based on data from 2000 to 2019 on five critical metals in China (copper, aluminum, nickel, antimony, and titanium), this study employs a series of econometric methods, such as fixed-effects regression and moderating effects, to examine the influence of green eco-innovation on primary and recycling supply of critical metals, as well as the underlying mechanisms. The findings indicate: (1) Green eco-innovation has an inverted U-shaped impact on the primary supply of bulk critical metals, and it is currently in the declining phase of the curve. (2) Green eco-innovation has a U-shaped impact on the recycling supply of critical metals and the primary supply of minor critical metals. The former is currently in the rising phase of the curve, while the latter is in the declining phase. (3) The impact of green eco-innovation on the supply of critical metals is stronger in industrially underdeveloped regions. (4) The improvement of energy efficiency, optimization of energy structure, and strengthening of environmental regulations enhance the impact of green eco-innovation on the supply of critical metals. Finally, the optimization of the energy mix is conducive to securing the supply of key metals. This study provides a theoretical basis for utilizing green eco-innovation to achieve a green supply of critical metals and enriches the theoretical research on green eco-innovation.