Treating high-strength fresh leachate is challenging and of great interest due to the inherent variability in its physical and chemical characteristics. This research aims to enhance the efficiency of the anaerobic hybrid reactor (AHR) series in treating high-strength fresh leachate and achieving biogas generation from fresh leachate at ambient temperatures. The AHR series used consists of two serially connected reactors termed the first anaerobic hybrid reactor (AHR-1) and the secondary anaerobic hybrid reactor (AHR-2). AHR-1 treated high-concentration fresh leachate with an organic loading rate (OLR) between 5 and 20 kgCOD/m3·d. AHR-2 treated the effluent from the first tank and removed organic matter from the system. The experiment was conducted for 210 days, showing that an OLR of 10 kgCOD/m3·d resulted in the most suitable COD removal efficiency, ranging from 82 to 91%. The most suitable OLR for biogas production was 15 kgCOD/m3·d. The AHR series proved to be an efficient system for treating high-strength fresh leachate and generating biogas, making it applicable to leachate treatment facilities at waste transfer stations and landfill sites. Treating leachate and utilizing it as a renewable energy source using the AHR series presents a practical and efficient waste management approach. High-strength leachate can be effectively treated with the AHR series; such methods may be integrated into industries treating leachates with high COD values.