A method of starting an internal combustion engine of a vehicle with a hybrid-electric powertrain having an internal combustion engine, a generator, and a high-voltage battery pack, is provided. An internal combustion engine start input signal is received. A load on an electric motor and generator is determined. The internal combustion engine receives torque transmitted from the electric motor and generator when the load on the electric motor and generator is below a predetermined load threshold. The internal combustion engine receives torque from an exogenous starting device when the load on the electric motor and generator is above the predetermined load threshold.