Fossil fuel depletion and environmental concerns have driven the urgent need for renewable energy sources, prompting researchers to focus on developing robust energy storage methods to facilitate the transition to sustainable energy in industry. Among the promising energy storage solutions, supercapacitors have garnered significant attention due to their high power density and rapid charge-discharge capabilities, making supercapacitor electrode materials crucial. Reduced graphene oxide (rGO) suffers from strong re-stacking during chemical reduction, which in turn severely limits its performance in supercapacitors and other electrochemical applications. This work, aimed to engineer the active sites in rGO through nickel (Ni) doping. In this work, the oxidation of graphite using an improved Hummer’s method before the chemical reduction of graphene oxide using ascorbic acid was performed to start the Co-precipitation method. The XRD analysis of the Ni-doped rGO nanocomposite confirmed the formation of rGO and metallic Ni nanoparticles exhibiting a face-centered cubic (FCC) structure, with average crystallite sizes of 1.94 nm for pure rGO and 1.16 nm for 25 wt% Ni-doped rGO nanoparticles. Morphological examinations revealed that the undoped rGO and 25 wt% Ni-doped rGO possessed porous structures with irregularly shaped nanosheets/flakes and nano rose flower-like structures, respectively, and the 25 wt% Ni-doped rGO nanoparticles had a significantly higher BET surface area of 354.1 m²/g compared to 261 m²/g for the pure rGO. UV-visible spectral analysis indicated an increase in absorbance values and a red shift in the peak position from 241 nm for rGO to 328 nm for the 25 wt% Ni-doped rGO, with the calculated band gap of the Ni-doped rGO composite (1.84 eV) being lower than that of the undoped rGO (3.13 eV); FTIR spectroscopy confirmed the presence of M-O bonds (where M = Ni), indicating successful doping and the doped rGO samples exhibited improved thermal properties. Electrochemical measurements revealed that the 25 wt% Ni-doped rGO nanoparticles exhibited the highest specific capacitance of 634.7 F/g at 10 mV/s, significantly higher than the 365.2 F/g of the undoped rGO nanoparticles, and the energy density and power density of the 25 wt% Ni-doped rGO nanoparticles were 14.104 Wh/kg and 417.418 W/kg, respectively. These results suggest its potential application in energy storage devices. Keywords: Graphene oxide, Reduced Graphene oxide, Nickel Doping, supercapacitor.