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The accumulation of acidic by-products, particularly volatile fatty acids (VFAs), during the anaerobic digestion (AD) of landfill leachate frequently leads to system instability. This study enhanced the stability and methane production capacity of the landfill leachate AD system by optimizing the feeding strategy. An intermittent dosing and gradient loading strategy successfully promoted the targeted enrichment of methanogens and significantly improved the system’s tolerance to high organic loads. Experimental results indicated that at a chemical oxygen demand (COD) loading rate of 10,000 mg/(L·d), the COD removal efficiency reached 95.06%, and cumulative methane production reached 228.08 mL/g volatile solids (VS), representing a more than threefold increase compared to the initial domestication stage (71.92 mL/g VS). This study highlights the critical role of feeding strategy optimization in promoting the enrichment of methanogens, specifically Methanosaeta and Methanosarcina. These findings provide a novel technical approach and a theoretical foundation for enhancing the resource recovery efficiency and environmental performance of landfill leachate AD systems. Graphical Abstract