One of the major challenges in educational reform is supporting teachers and the profession in the continual improvement of instruction. Research-practice partnerships and particularly networked improvement communities are well-suited for such knowledge-building work. This article examines how a networked improvement community with eight school-based professional learning communities--comprised of secondary science teachers, science and emergent bilingual coaches, and researchers--launched into improvement work within schools and across the district. We used data from professional learning communities to analyze pathways into improvement work and reflective data to understand practitioners' perspectives. We describe three improvement launch patterns: (1) Local Practice Development, (2) Spread and Local Adaptation, and (3) Integrating New Practices. We raise questions about what is lost and gained in the transfer of tools and practices across schools and theorize about how research-practice partnerships find footholds into joint improvement work.