This study presents the nonlinear response and energy harvesting of a parametrically excited buckled beam subject to subharmonic resonance excitation. The excitation frequency is set close to twice the natural frequency of the first vibration mode in the postbuckling domain. The equation of motion exhibits quadratic and cubic nonlinearities. A reduced-order model based on the Galerkin’s method is obtained. The electromechanical equations of motion are presented. The temporal equations are numerically integrated to solve for the nonlinear response and the output voltage while increasing the excitation amplitude. The response shows a period doubling bifurcation that leads to chaos and co-existence of small-amplitude vibrations and snapthrough motions. A bifurcation diagram is obtained that shows all possible attractors with the excitation amplitude being the control bifurcation parameter. The root-mean-square of the output voltage is presented for different response patterns. The large-ampltidue periodic snapthrough response was found to generate the maximum power.