The present study represents a simple and scalable method that involves in situ polymerization of cobalt chloride (CoCl₂·6H₂O) doped aniline in the presence of graphene nanoplates (GNPs) in HCl medium, for the preparation of CoCl₂ doped polyaniline (PANI)/GNP composites (PGC) as a supercapacitor electrode material with noteworthy performance. The maximum specific capacitance and energy density of the PGC composites were found to be ≈634 F g⁻¹ and ≈427 W h kg⁻¹, respectively, at a 10 mV s⁻¹ scan rate. Through judicious control of the GNP content and CoCl₂ doped PANI in the composites, a very high electrical conductivity (≈12.2 S cm⁻¹) was achieved at unprecedented low GNP content. The PGC composites also exhibited high alternating current (AC) electrical conductivity in the frequency region of ∼10¹ to ∼10⁷ Hz. The morphology of the composites was successfully studied by field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM).