In this study, nanostructured carbon spheres were fabricated from leather leaf via hydrothermal carbonization and chemically activated with KOH. Different hydrothermal carbonization temperatures were used. The microtopographic, compositional, and structural characteristics and the surface properties of the synthesized material were then investigated via scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nitrogen adsorption-desorption, and Raman spectroscopy. Results indicated that the KOH-activated sample synthesized with hydrothermal procedure leads to spheroidal nano-porous amorphous carbon particles with an average size of 3-5 micrometers. The nano-porous carbon spheres exhibited remarkable material properties such as high specific surface area (1342 m2 g–1) and a well-developed porosity with a distribution of micropores 2 nm wide. These properties led to good electrochemical performance as supercapacitor electrodes. The electrochemical investigations through a three-electrode cell in an aqueous electrolyte have also confirmed the capability of the synthesized activated carbon nano-particles as promising candidates for supercapacitor applications. In particular, a specific capacitance of 374 F g-1 was achieved at a current density of 2 A g-1. Manuscript profile