Workaholism and overcommitment are often defined as irrational or obsessive attachments to work, characterized by excessive work investment with negative consequences for health and well-being. However, the relationship between these constructs remains underexplored. In this study, we hypothesized that workaholism and overcommitment represent different stages of the same work addiction dynamic, with overcommitment mediating the relationship between workaholism and burnout. Additionally, we proposed that job satisfaction reinforces this addiction dynamic, strengthening the relationship between workaholism and overcommitment over time. Utilizing data from a three-wave longitudinal study (time-lag = 1 month) involving Italian employees, we tested a moderated mediation model. Our findings indicated that overcommitment at T2 fully mediated the relationship between workaholism at T1 and job burnout at T3. Moreover, job satisfaction at T2 significantly moderated this pathway, suggesting that higher job satisfaction leads to a stronger relationship between workaholism and overcommitment over time. In conclusion, our study highlights the exacerbating effect of job satisfaction on the link between workaholism and overcommitment, which can, in turn, increase employees’ burnout. This research represents the first longitudinal examination of workaholism and overcommitment as stages within the same process, rather than as distinct constructs.