MgO-doped nickel oxyhydroxide (MgO–NiOOH) nanostructures were successfully synthesized via a hydrothermal route. The obtained samples were characterized using XRD and FT-IR analyses and subsequently employed for electrode fabrication in supercapacitor applications. The engineered morphology provides abundant electrochemically active sites, thereby facilitating rapid charge transfer and enhanced charge-storage behavior. The fabricated electrode delivered a specific capacitance of 650 F g⁻¹ at 1 A g⁻¹ in 1 M KOH electrolyte, along with excellent cycling stability. These findings demonstrate that MgO doping in NiOOH frameworks significantly improves electrochemical performance, making them promising candidates for advanced energy storage devices