<p>This study explores professional learning (PL) as knowledge co-construction in a multistakeholder professional learning community (PLC) in China. The PLC, involving teachers, academics, and policymakers, was designed with a top-down structure to support a curriculum reform but aimed to foster bottom-up collaborative inquiry. PL is conceptualised as knowledge co-construction in this study through the lens of epistemic fluency. Data from workshop transcripts and phased interviews were analysed using the Progressive Inquiry Model (PIM) and the concept of organisational capability. Findings reveal that the development of stakeholders' epistemic fluency was the key mechanism driving the PLC's evolution from a rigid, hierarchical structure to an adaptive, co-configurative learning system. This transition was propelled by the emergence of “shared epistemic fluency” within the group. The analysis also uncovered a strategic adaptation termed “compromised epistemic fluency,” wherein academics maintained a static expert role to steward the PLC's primary goal, contrasting with the role fluidity exhibited by teachers and policymakers. The study suggests that epistemic fluency provides a diagnostic and design lens for understanding multi-stakeholder collaborations, nuancing its application in such contexts by proposing the concepts of shared and compromised epistemic fluency. It concludes that organic PL can be cultivated within mandated structures by prioritising the development of integrative knowledge work.</p>