Prevalent new paradigms are emphasizing the need for more powerful learning opportunities that meet the needs of 21st century learners. One way to change education to better meet the needs of the 21st century is to reimagine school architecture. The purpose of this research was to study the ways practitioner inquiry can serve as a mechanism for mediating and supporting teacher professional development in a newly built school that uses space differently. The elementary school that is the context of this study built a 21st century community learning center with innovators in architectural design that encourage a new way of teaching. A strong focus on professional development as teachers prepared for the new building was essential. Recognizing that professional development would be challenging in the transition to the new space, those responsible for professional development used practitioner inquiry to systematically and intentionally study their practices. To investigate ways these professional developers used practitioner inquiry to understand their experiences in mediating teacher professional learning, this research was theoretically oriented by hermeneutics. During the first year in the new school building, the participants and researcher simultaneously engaged in the inquiry cycle and hermeneutical circle. Using literature, historical artifacts, field notes, professional development documents, and interviews as data, this work is organized through pre-understandings, understandings, and new understandings of the experiences the participants encountered as they led professional development efforts during the first year in the new building space. This study's findings suggest the value of inquiry for professional developers, and demonstrate the value of implicit inquiry as professional development. It provides insight into the need for professional development to be supportive of chaotic transitions during reform efforts, and discusses the importance of inquiry data for renegotiating existing school structures. This study demonstrates that 21st century school reform is not easy, but possible. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]