Professional development is an important part of creating a culture of continuous school improvement to maximize student learning. Rarely do we measure the impact of professional development on teacher learning, implementation and student outcomes. This study describes a professional development strategy for elementary teachers to promote curriculum implementation and instructional strategies of student discourse and reasoning in one Connecticut school district. The study also includes assessment of teacher implementation of the strategies and student learning outcomes. Data sources include teacher surveys, classroom observations and student achievement data. Findings indicate that the professional development model was effective in increasing teachers' understanding and implementation of instructional strategies which promote student discourse and reasoning. Analysis of teacher feedback suggests an improved learning environment for students. Students were more independent, demonstrated their reasoning more frequently and were more willing to take academic risks. However, these effects were not consistently linked to improvement in standardized achievement tests. This study responds to a need identified in the literature for more robust evaluations of professional development that include analysis of teacher implementation and student outcomes. The observation and survey instruments as well as the professional development model itself could be used in other districts.