This paper reports on a qualitative, grounded-theory-based study that explored the motivations of science and engineering faculty to engage in teaching professional development at a major research university. Faculty members were motivated to engage in teaching professional development due to extrinsic motivations, mainly a weakened professional ego, and sought to bring their teaching identities in better concordance with their researcher identities. The results pose a challenge to a body of research that has concluded that faculty must be intrinsically motivated to participate in teaching professional development. Results confirmed a pre-espoused theory of motivation, self-determination theory; a discussion of research literature consideration during grounded theory research is offered. A framework for motivating more faculty members at research universities to engage in teaching professional development is provided.