<![CDATA[Educational reform literature debates whether teacher professionalism is primarily driven by top–down change management or by collaborative professional culture within schools. While change initiatives often focus on structural and managerial reforms, their impact on teachers’ professional growth remains inconsistent without strong collective learning mechanisms. Addressing this theoretical tension, this study investigates how learning communities mediate the relationship between change management and teacher professionalism. Using a mixed-methods explanatory sequential design, data were collected from 220 senior high school teachers and nine key informants. Structural analysis using PLS-SEM reveals that change management strongly predicts learning communities (β = 0.903; p < 0.001), yet its direct effect on teacher professionalism is comparatively modest (β = 0.184; p = 0.023). In contrast, learning communities exert a dominant direct influence on professionalism (β = 0.737; p < 0.001) and serve as the primary transmission mechanism of managerial reform (β = 0.665; p < 0.001), indicating that the majority of reform impact operates through collaborative professional culture rather than direct managerial intervention. Qualitative findings reinforce this interpretation by showing that participatory leadership, dialogic vision-building, and sustained reflective collaboration transform structural change into professional commitment and practice. ]]>
