Some contemporary urban educational reformers believe that empowering principals with increased school-based autonomy will help them lead educational improvement more effectively. We consider this popular reform idea by examining how principals experienced and exerted autonomy in different forms in two distinct eras in New York City. Our findings suggest that principal autonomy as a centrally planned reform strategy for urban education encounters a Goldilocks dilemma: principal power is almost inevitably too hot or too cold, but never just right. However, principals can and do assert self-sourced autonomy in which they recognize and exercise whatever power they may have within prevailing organizational constraints, conditions, and restrictions. We conclude by examining implications.