<p>University-school partnerships provide opportunities for teacher professional learning and collaborative research, yet relatively little is known about how university researchers’ roles shape these processes. This study investigates two distinct researcher roles, i.e., co-author and authority, and their impact on research collaboration and teacher learning. Using a qualitative multi-case design, data were collected from four research cases in China through group and individual interviews, supplemented by textual data. Findings reveal that in the co-author pattern, the university researchers positioned themselves as an equal collaborator, facilitating joint decision-making, shared intellectual contributions, and iterative revisions. While this approach slowed research production, it fostered deeper teacher engagement and sustained professional networks. In contrast, the authority pattern involved hierarchical structuring, where the university researchers led research conceptualisation, controlled decision-making, and structured writing tasks. This approach accelerated publication but limited schoolteachers’ agency, creating short-term research efficiency but weaker long-term collaboration. Drawing on social mechanism theory and professional capital theory, the study highlights trade-offs between efficiency and professional learning in university-school collaborations. These findings offer a mechanism-based understanding of role interactions, providing practical insights for designing sustainable and mutually beneficial research partnerships.</p>