Purpose The purpose of this paper is to analyze the moderation effect of over-commitment in the job crafting-well-being relationship, in the elderly care sector in Spain. Design/methodology/approach A cross-sectional design was implemented and a final sample of 353 participants were assessed using the Job Crafting Questionnaire, an adaptation of the Over-commitment Scale from the Effort-Reward Imbalance Questionnaire, and the General Health Questionnaire (GHQ-12). Findings A positive interaction between relational and task crafting and over-commitment is observed in the prediction of well-being levels. Specifically, the effect of over-commitment in the task crafting-well-being relationship proved to be statistically significant when opposed to low, medium and high levels of over-commitment. Additionally, the effect of over-commitment in the relational crafting-well-being relationship proved to be statistically significant only when opposed to medium and high levels of over-commitment. Finally, a direct and simple effect was observed between cognitive crafting and well-being, not moderated by over-commitment. Originality/value The moderating role of over-commitment in the job crafting-well-being relationship in the elderly care sector represents one of these attempts to better understand evidences of how work-related efforts modify a worker's psychological functioning and adaptation, which is the reason why, specially in contexts of uncertainty, its study becomes relevant.