Many educators have suggested that teachers hold the authority, and thus the responsibility, for initiating the curricular and instructional changes made within their own classrooms. One implication of this suggestion is that teachers be reflective about their practice. Yet, reflection is a difficult process that requires critical thought, self-direction, and problem solving, coupled with personal knowledge and self-awareness. As classroom teachers, the authors believe that thorough reflection and teacher inquiry are important and related assumptions of quality teaching. This article describes a study that utilized personal theorizing as a mechanism to guide the action research of individuals within an elementary preservice teacher cohort during their four-semester, teacher education program. Three distinct categories emerged as a result of the personal theorizing and action research process completed by the candidates: defining self, defining reflection, and defining professionalism. By identifying and defining their personal practice theories, candidates were able to describe their values and beliefs about teaching. Secondly, candidates were able to construct a personal definition of reflection. Originally, many of the candidates had viewed reflection as a reaction instead of a process. Lastly, reflection coupled with the action research component became ingrained in the majority of the candidates as not only a requirement of their preservice program but also a requirement of their profession.