Hydrogen dissociation is a key step in almost all hydrogenation reactions; therefore, an efficient and cost-effective catalyst with a favorable band structure for this step is highly desirable. In the current work, transition metal-based C20 (M@C20) complexes are designed and evaluated as single-atom catalysts (SACs) for hydrogen dissociation reaction (HDR). Interaction energy (Eint) analysis reveals that all the M@C20 complexes are thermodynamically stable, whereas the highest stability is observed for the Ni@C20 complex (Eint = −6.14 eV). Moreover, the best catalytic performance for H2 dissociation reaction is computed for the Zn@C20 catalyst (Eads = 0.53 eV) followed by Ti@C20 (Eads = 0.65 eV) and Sc@C20 (Eads = 0.76 eV) among all considered catalysts. QTAIM analyses reveal covalent or shared shell interactions in H2* + M@C20 systems, which promote the process of H2 dissociation over M@C20 complexes. NBO and EDD analyses declare that transfer of charge from the metal atom to the antibonding orbital of H2 causes dissociation of the H-H bond. Overall outcomes of this study reveal that the Zn@C20 catalyst can act as a highly efficient, low-cost, abundant, and precious metal-free SAC to effectively catalyze HDR.