Innovation fuels efforts to improve teaching and learning in schools. However, the innovation of school-based practitioners is rarely realized beyond their own schools. Amplifying the work of teacher innovators to bolster school improvement efforts requires research to understand how education practitioners recognize problems, develop solutions, and scale-up their own initiatives. Collaborative governing arrangements such as Networked Improvement Communities (NICs) are becoming a popular means to initiative educational change. Educational researchers must systematically examine the dimensions of perceived collaborative arrangements within the context of school improvement to understand both the limitations and potential of this new governing trend for empowering stakeholders that have been excluded from education policymaking. This case study examines how an early-career classroom teacher managed to scale-up a relatively unknown math program from a single-school pilot into a 30-school regional implementation. The teacher innovator effectively leveraged the relational infrastructure of government-sponsored an educational improvement network in England. This inter-organizational recruitment strategy is explained by a new network mechanism called Star Coalescence. Star Coalescence describes a series of activities resulting in two collaborators developing new and enduring relationships with each other’s contacts. This complex social phenomenon is significant because it can trigger a cascade of triad closures between two sparsely connected professional networks, resulting in an efficient means for scaling-up a new initiative across large school systems.