Sustainable and low-cost electrodes are essential for advancing practical electrochemical energy storage. Herein, recycled Corchorus olitorius (jute fiber) converted into hierarchically porous activated carbon electrodes for supercapacitor by hydrothermal pretreatment and KOH activation. The hydrothermal process decomposes biomass, while KOH activation generates micro–mesoporous carbon framework facilitating rapid ion transport and efficient charge storage. The optimized jute-derived carbon exhibits a high specific surface area of ~ 1903 m2 g-1. In 6 M KOH electrolyte, the electrode exhibits specific capacitance of 346 F g-1 at 1 A g-1 and retains about 96% of capacitance after 10,000 charge–discharge cycles. An assembled symmetric supercapacitor in 1 M Na2SO4, achieves an energy density of 15.44 Wh kg-1 at a power density of 402.8 W kg-1. This confirms the potential of biomass-derived jute carbon as a sustainable electrode for supercapacitor.