Adopting a dynamic within-person perspective on employee innovation, the present study investigates the role of situational job autonomy and momentary work engagement as day-level correlates of innovative behaviour. Anticipating individual differences in the strength of these intraindividual associations, we propose dispositional creative self-efficacy (CSE) to serve as a cross-level moderating influence amplifying the day-specific predictive power of autonomy and work engagement for innovative behaviour. Hierarchical linear modelling analyses of the nested data from 123 employees surveyed over 5 consecutive work days suggest that both autonomy and work engagement positively predict self-reported innovative behaviour on a daily basis. Whereas the engagement–innovation link emerges as homogenous across persons, results indicate that the daily within-person effect of autonomy on innovative behaviour varies significantly as a function of CSE such that it is greater for individuals who hold higher rather than lower CSE beliefs. Implications for future research, limitations, and practical implications are discussed.