Abstract: Single hydrogen-doped endohedral fullerene H@C₆₀ and exohedral fullerene cation HC₆₀⁺ are investigated via semiempirical and first principles calculations. The most stable configuration of H@C₆₀ corresponds to the H atom on the center of the C₆₀ cage, a result consistent with the recent Bingel transformation experiments. The geometry of HC₆₀⁺ is quite similar to its neutral species. Its electronic structure is characterized by a strong localization of the LUMO on the dopant H site and a half-reduced HOMO-LUMO energy gap relative to that of C₆₀.The agreement between the calculated and observed electronic spectra of HC₆₀⁺ confirms its oxidation state in solution.