The joint optimization of partial response continuous phase modulation (CPM) parameters is addressed. For fixed modulation order and memory length, the modulation index, the symbol rate and the phase pulse shape are considered as degrees of freedom. In particular, we drop the restriction of “classical” phase pulses and we allow for custom shapes, which are parametrized through Bezier curves. In order to deal with the many variables involved, an evolutionary algorithm is employed for numerical optimization. The optimization metric is related to the extrinsic information transfer (EXIT), under the assumption that CPM is serially concatenated with an outer convolutional encoder, as it is the case for several practical systems. The presence of high adjacent channel interference (ACI) is explicitly accounted for in the optimization process. We show that the proposed optimization strategy can effectively exploit the power-bandwidth trade-off. Nevertheless, only moderate improvements are achievable in comparison to state-of-the-art serially concatenated systems.