With this article, we describe and analyze the experience of a scientist as she delineated the meaning of scientific inquiry and developed a new professional identity as a science teacher educator. Our inquiry adopted a self-study methodology with a variety of data sources, including sixteen-weeks of journal entries, critical friends' meetings and reflections, video and audio-taped lessons and students' artifacts. The self-study process captured her conflict between scientific inquiry in the classroom and her chemistry research. We captured three stages of her understanding of scientific inquiry. The idea of "authentic scientific novice research" finally resolved her conflicts. This study also revealed three factors that influenced the formation of her professional identity (i.e., competing identities, contextual influences, and personal struggles). This finding and resulting conclusions not only report the evolution of personal understanding, but also bring out the discussion of teacher educator development, especially for those transitioning to science education from natural sciences.