Fullerenes have emerged as functional catalytic nanomaterials in a plethora of applications, mainly due to their distinctive electronic structures. Therefore, we investigated the electronic structures of different fullerenes (C 60 , C 70 , C 76 , C 84 , and C 100 ) using density functional theory (DFT) calculations to identify the most suitable candidate as a hydrogen evolution reaction (HER) catalyst. The calculations showed that C 76 exhibits the most convenient electronic structure suitable for HER. Consequently, the synergy between C 76 nanospheres and nickel foam substrate as a highly efficient HER catalyst has been demonstrated and discussed. The results showed that C 76 nanospheres−Ni foam exhibits a superior catalytic activity with an overpotential of 20 mV vs RHE at −10 mA cm −2 , which is almost the same as the benchmark Pt/C catalyst. The calculated free energy and band structure revealed a significant increase in the electron density at the C 76 /Ni foam interface, indicating the synergy between C 76 nanospheres and Ni. Moreover, the exchange current density (J 0 ), charge transfer coefficient (α), and mass activity (MA) were determined to elucidate the kinetics of the HER upon loading the Ni foam with different masses of C 76 . The electrodes containing 0.48 and 0.53 mg of C 76 exhibited high α and J 0 , revealing very fast HER kinetics on their surfaces. This observed drastic increase in J 0 is accompanied by a reduction in the activation barrier, which is in agreement with the DFT results.