Abstract: Biodegradable film mulching is one of the most critical technologies to overcome the dual challenges of agricultural plastic pollution and greenhouse gas (GHG) emissions. However, it is often required to optimize the key film properties—color and thickness—on the agronomic productivity and net environmental footprint. This study aimed to identify the optimal mulching strategies for high crop yield with a better environment during peanut cultivation. A field experiment was conducted with nine treatments: a no-mulch control (CK), conventional 0.010 mm polyethylene films (black and white), and biodegradable films of two colors (black, BDM; white, WDM) and three thicknesses (0.008, 0.010, and 0.015 mm). A systematic measurement was carried out to determine the peanut yield, water use efficiency (WUE), as well as the fluxes of N₂O, CH₄, and CO₂ using the static chamber-gas chromatography. Global warming potential (GWP) and greenhouse gas intensity (GHGI) were also calculated to assess the overall climate impacts. Results demonstrated that all mulching treatments significantly improved the peanut yield and WUE, compared with the CK. All mulches were also significantly reduced the cumulative N₂O emissions, GWP, and GHGI (P<0.05). Concurrently. There was a weak CH₄ sink capacity in the soil. Furthermore, the agronomic and environmental performance of the biodegradable films was comparable to that of conventional films in the short term, indicating their viability as a sustainable alternative. Crucially, the color and thickness were identified as the key drivers of performance. In color, the white films produced an average yield 10.6% higher than black films of the same thickness (P<0.05). Thinner films also exhibited superior potential for GHG mitigation. The 0.008 mm white biodegradable film (WDM8) reduced the GWP by 41.8% and 24.4%, compared with its 0.010 and 0.015 mm counterparts, respectively (P<0.05). Similarly, the 0.008 mm black biodegradable film (BDM8) lowered GHGI by 7.4% and 19.1%, respectively, compared with the thicker black ones (P<0.05). Two context-dependent optimal strategies were proposed. First, the 0.008 mm white biodegradable film (WDM8) was recommended for the synergistic high yields and low carbon emissions, as it recorded the highest yield and one of the lowest GHGI values. Second, the 0.008 mm black biodegradable film (BDM8) exhibited no significant differences in yield and WUE from WDM8, thereby serving as another excellent mulching option for sustainable agricultural production.This finding can provide a scientific basis to optimize the targeted biodegradable film in climate-smart and sustainable agriculture.