Professional development designed to integrate key features of research-based professional learning has positive and significant effects on teacher practice and student achievement in mathematics when implemented in schools that meet specified technology-readiness criteria. Key features of research-based professional learning include intensive focus on content-specific and pedagogical practices aligned with new standards, sustained classroom-based and online support over multiple years, and professional learning for principals on monitoring and supporting teacher implementation of newly acquired practices. eMINTS (enhancing Missouri's Instructional Networked Teaching Strategies), a decade-old professional development program promoted inquiry-based instruction and learning, high-quality lesson design, community within classrooms among students and teachers, and technology-rich learning environments. This article describes the randomized trial evaluation study in 60 rural schools, designed to address limitations of previous evaluation studies and meet criteria of the national What Works Clearinghouse. Professional development was designed to integrate key features of research-based professional learning and had positive and significant effects on teacher practice and student achievement in mathematics when implemented in schools that meet specified technology-readiness criteria. Professional development was supplemented with written curricula and just-in-time learning through online courses for extended support. Principals worked with eMINTS consultants to support implementation and integrate eMINTS with other initiatives. Teacher survey results indicated a statistically significant effect in inquiry-based learning and high-quality lesson design between the treatment and control groups, with positive yet not statistically significant differences in community of learners.