Fixed-frequency negative-ion photoelectron spectra of tricarbonyl(eta(5)-methylcyclopentadienyl)manganate(0), Cp*Mn(CO)(3)(-), are obtained at 355 and 532 nm. The adiabatic electron affinity of tricarbonyl(eta(5)-methylcyclopentadienyl)manganese(I), Cp*Mn(CO)(3), as obtained from the experiments, is 0.5 +/- 0.1 eV, and the vertical ionization potential of the anion is 1.0 +/- 0.1 eV. By combining our electron affinity results with literature gas-phase acidity estimates for Cp*Mn(CO)(3) we determine that the C-H bond dissociation energy, D[H-CH2C5H4Mn(CO)(3)(-)], in the anion is 2.2 +/- 0.8 eV.