<p>The rising accumulation of agricultural plastic waste has become a serious environmental and scientific concern as it persists in nature for a longer time and causes environmental pollution. To address this problem, we upcycled agricultural plastic waste into activated carbon and employed it as an electrode material for high-performance supercapacitor applications. Field emission scanning electron microscopy (FESEM) and Brunauer–Emmett–Teller (BET) analysis confirmed a well-developed porous architecture (average pore radius of 1.18&#xa0;nm and surface area 1013.05 m²g⁻¹) in the as-synthesised material. In a three-electrode configuration, the agricultural plastic waste-derived activated carbon’s electrode delivered an outstanding specific capacitance of 351.48 Fg⁻¹ at a current density of 0.25 Ag⁻¹ in 1&#xa0;M H₂SO₄. The symmetric supercapacitor device (two-electrode) exhibits a specific capacitance of 127.88 Fg⁻¹ at a current density of 0.25 Ag⁻¹. The device shows a high-power density of 7996.60 Wkg⁻¹ at an energy density of 10.44 Whkg⁻¹. The device exhibits remarkable cyclic stability, with 92.79% capacitance retention over 8000 cycles. The device depicts a high rate-capability of 90.46% (at current density 1 Ag⁻¹) and coulombic efficiency of 93.9% (at current density 1 Ag⁻¹). Overall, these result presents a sustainable approach for utilization of agricultural plastic waste for high-performance supercapacitor applications.</p> Graphical Abstract <p></p>