We used ab initio methodology for the computation of the potential energy curves of the doublet and quartet electronic states of the MgO(+) cation correlating with the four lowest dissociation limits. Using these highly correlated wavefunctions, we calculated their spin-orbit coupling and transition moments. We deduced an accurate set of spectroscopic constants for this cation. Most of the data relative to the electronic excited states of this cation are predictive in nature. Moreover, our potentials, transition moments and spin-orbit coupling evolutions are incorporated into Fermi golden rule calculations to deduce the natural lifetimes of the lowest MgO(+)(1(2)Sigma(+)) ro-vibrational levels. Finally, our potentials were used for the prediction of the single ionization spectrum of MgO.