LAUSR

As inter‐school collaboration becomes a key strategy for educational improvement, the role of system leaders in sustaining such efforts has drawn increasing attention. Yet empirical research in the Chinese context remains limited. This study examines how system leaders facilitate sustainable inter‐school collaboration in China’s Greater Bay Area, focusing on a successful long‐term school partnership established under the government‐supported Sister School Scheme. Using a qualitative case study, we analyzed interview data from five principals—each holding multiple roles—as our primary data source. Documentary materials (e.g., policy texts and school reports) were used to triangulate and contextualize the interview findings. Thematic coding analysis shows that these leaders enacted system leadership by shifting among four interrelated roles—thought advocate, practice pioneer, boundary spanner, and resource mobilizer, each linked to specific leadership practices. The study advances international understanding of system leadership by showing how principals lead across school and system boundaries in China’s policy‐driven, cross‐border context. It also offers practical insights for sustaining inter‐school collaboration.