Next-generation energy storage systems require green and renewable electrodes with a high specific capacity, which combine biomass waste and bimetallic hydroxide synergically to satisfy environmental enhancements and economic benefits. Herein, a novel approach to improving the electrical conductivity of bimetallic materials by in situ growing NiCo layered double hydroxides (LDHs) with pseudocapacitance capability on KMnO₄-activated fungus bran-derived carbons (FBCs) is reported, achieving improved electrochemical performance in supercapacitors (SCs). The hierarchical porous FBC substrate contributes to the homogeneous growth of the LDHs and high electronic and ionic conductivity. The optimal composite (FBC/NCL-3) with a 3D interconnected structure provides a specific capacitance of 1938 F g⁻¹ at a current density of 1 A g⁻¹. Correspondingly, the hybrid battery-SC device composed of FBC/NCL-3 and FBC provides favorable stability (76% specific capacity retention at 5 A g⁻¹ for 3000 cycles) with an operating voltage of 1.4 V and a high energy density of 37.3 Wh kg⁻¹ at a power density of 695.6 W kg⁻¹. This work demonstrates a promising strategy using FBC as a substrate for growing LDH materials aiming to achieve high-performance SCs.