In our presentation we will illustrate the important role that course work in mathematics might play in supporting the mathematics specialist's mathematical understanding. Additionally, we offer examples of how the mathematics specialist might adapt these understandings as she engages in new teaching and leading situations. As we do so, we provide a glimpse of the range and quality of activities that the mathematics specialist might engage in as she supports teachers and students. We also illustrate how her expertise takes on a life of its own as the mathematics specialist continues to meet the day-to-day challenges.