Most of us have at one point speculated about why one individual grew up to be honest and fair while another became wicked and untrustworthy. In the current review, we present the case that new directions in the empirical study of moral personality development are needed. We set the stage for this future work by presenting six propositions that should serve as the foundation for future research in the field. We conclude by providing an example of how using a more integrative and inclusive framework for studying personality can readily incorporate these propositions.