Developing advanced electrode materials with exceptional properties is vital for creating energy storage systems capable of achieving high energy and power densities. At present the focus has shifted from single metal oxides to mixed metal oxides for enhanced charge storing performance. In the present work, the neat CuGa2O4 and its g-C3N4 based composites (75 % g-C3N4@CuGa2O4 and 85 % g-C3N4@CuGa2O4) were developed through the hydrothermal method and assessed their suitability supercapacitor application. XRD analysis revealed the cubic CuGa2O4 formation. SEM analysis was carried out to study the surface morphology of the synthesized samples and it indicates that the incorporation of g-C3N4 influences the significant surface modification such as heterogeneity and agglomeration compared to that of relatively smooth yet cracked surface of CuGa2O4. XPS and EDS mapping was further performed to confirm the oxidation state and elemental distribution of the synthesized material. Electrochemical analysis confirmed a notable enhancement in charge storage capacity, driven by improved electrical conductivity. Among the developed composite materials, 85 % g-C3N4@CuGa2O4 exhibited the highest specific capacitance of 483.3 Fg-1. It was observed that the asymmetric supercapacitor device fabricated using the composite material (85 % g-C3N4@CuGa2O4) developed as the positive electrode has achieved a high energy density of 31.13 W h kg−1 and a power density of 703.12 W kg−1, along with outstanding cycling stability, retaining 99 % capacitance after 5000 cycles. Data obtained from different studies infer that the g-C3N4-modified CuGa2O4 composites can be used as an efficient electrode material for the fabrication of high-performance supercapacitor.