A current trend in organizational job design is to provide employees increased autonomy to enhance their performance. Using the Job Demands-Resources (JD-R) theory as a working framework, the present study proposes proactive vitality management and work engagement as sequential mediators of this relationship. Thus, we test a parsimonious model that encompasses both individual strategies (i.e., proactive vitality management) and affective-cognitive (i.e., work engagement) factors as explanatory mechanisms in the link between autonomy and performance. Data from 256 Romanian employees were gathered and analyzed via structural equation modeling. The results provided support to our model. Specifically, we found proactive vitality management and work engagement to fully mediate the relationship between autonomy and performance. As such, our model validates the theoretical assumption of the JD-R theory that employees who engage in individual strategies (i.e., proactive vitality management) can capitalize on existing job resources (i.e., autonomy) to increase their well-being (i.e., work engagement) and performance. Furthermore, by identifying proactive vitality management as a mediator in the relationship between autonomy and performance, we provide practitioners with a set of proactive behaviors that can complement resource-replenishing activities (e.g., coffee break) in securing and sustaining high energy levels at work.