A dicobalt tetrakis(Schiff base) macrocycle has recently been reported to electrochemically catalyze the reduction of H+ to H-2 in an acetonitrile solution. Density functional theory (DFT) calculations using the omega B97X-D functional are shown to produce structural and thermodynamic results in good agreement with the experimental data. A mechanistic model based on thermodynamics is developed that incorporates electrochemical and magnetic details of the complex, accounting for electron-spin reorganization of the metal center after redox steps. The model is validated through a comparison of the predicted electrochemical potentials with the irreversible cyclic voltammogram of [Co2LAc](+), which shows redox-coupled spin-crossover (RCSCO) behavior for the Co-II/III transitions. Using our model, we predict the thermodynamically favored mechanism of H-2 evolution by [Co2L](2+) to be one of heterolytic proton attack on a (Co2L)-L-II(mu-H)](+) species. Understanding the electronic details and thermodynamically preferred mechanism of this catalyst will aid in improving its efficiency and the future design of bimetallic Co-based H+ electrocatalysts. Also, this work will assist in the future DFT modeling of bimetallic RCSCO complexes.