As organizations increasingly rely on innovation to remain competitive, understanding how to cultivate innovative work behavior (IWB) among employees has become a strategic priority. This study, rooted in the Job Demands&ndashResources (JD-R) framework, examines the roles of proactive personality, inclusive leadership, and climate for innovation as critical antecedents that foster employee engagement (EE) among millennial professionals in the Indian information technology (IT) sector. It further investigates how EE contributes to IWB directly and indirectly via constructive deviant behavior (CDB), a form of intentional deviation from organizational norms aimed at generating positive outcomes. Additionally, the study explores how challenge and hindrance stressors differentially moderate the relationship between EE and CDB, as well as the overall indirect pathway from EE to IWB through CDB. Data were collected through a structured questionnaire administered to millennial IT employees across India, and analyzed using partial least squares structural equation modeling (PLS-SEM). Findings reveal that EE significantly mediates the influence of proactive personality, inclusive leadership, and climate for innovation on IWB. CDB acts as a positive behavioral conduit translating engagement into innovation, particularly under conditions of high challenge stressors and low hindrance stressors. The moderated mediation results underscore the critical role of job demands in shaping the engagement-to-innovation pathway. Theoretically, this study extends the JD-R model by integrating CDB as a mediating mechanism and incorporating stressor types as boundary conditions. It advances the literature on positive deviance and innovation by elucidating how personal and contextual resources interact with work stressors to drive innovative outcomes.Practically, the findings offer actionable insights for HR professionals and organizational leaders. Interventions should focus on fostering inclusive and innovation-supportive climates, promoting proactive behavior, and managing stressor types to optimize engagement and innovation. The study is particularly relevant to organizations seeking to harness the creative potential of millennial employees in dynamic and high-pressure environments.