One-to-one mobile technology integration is the goal of increasing numbers of school districts each year, and many factors exist to consider when measuring success. The research problem for this qualitative study focused on one of the critical components for measuring success: the need for effective teacher professional development. The purpose of this study was to examine (a) principles and practices to facilitate the integration of one-to-one mobile technologies into professional learning experiences, and (b) the perceptions of technology instructional coaches regarding changes in teachers' practice and attitudes following professional development. The conceptual framework included Knowles's theory of andragogy and Koehler and Mishra's TPACK framework. In two rounds, 19 interviews were conducted with 13 technology instructional coaches. Thirteen coaches were interviewed in round one and from that data six high level coaches were identified for a second round of interviews. The data from both interview rounds were analyzed and coded to identify themes and categories. The key findings revealed that effective one-to-one mobile technology integration requires supportive leadership; building culture and relationships; instructional design with standards and frameworks; building collaborative, job-embedded teacher agency; and personalized learning with differentiated delivery. All stakeholders could use the key results to make informed decisions for planning and implementing professional learning opportunities. This study may affect positive social change by enhancing how technology is integrated into teaching and learning through increased teacher engagement in professional learning.