Hydrogen evolution reaction (HER) has captivated the interest of researchers due to ever increasing demand for future sources of energy. With the advancement in renewable energy resources, electrocatalytic production of hydrogen has been considered as the most suitable way for hydrogen production for fuel cells and combustion engines. Herein, we studied HER activity of transition metal doped C20 fullerene (M@C20) by means of adsorption energy, Gibbs free energy and electronic density calculations. Ni@C20 and Cu@C20 complexes provide the best HER activity with Gibbs free energy of −0.09 eV for each. Furthermore, electronic properties such as the density of states (DOS) and frontier molecular orbital analyses are performed which indicate that transition metal doping significantly alters the electronic properties of studied M@C20 complexes. Whereas the adsorption of hydrogen does not affect the electronic parameters much. The basic understanding of hydrogen adsorption mechanism together with analyses of electronic parameters is crucial for the synthesis of highly efficient electrocatalysts for hydrogen energy applications. The critical findings of this study declares that both Ni@C20 and Cu@C20 complexes can act as promising electrocatalysts for hydrogen evolution reaction with low overpotential.