Based on the cognitive appraisal theory of stress and team process perspective, through the analysis of three-stage questionnaire data from 123 teams, this study examines the mechanisms and boundary conditions through which team illegitimate tasks influence team job crafting behavior. The results show that team illegitimate tasks facilitate team job crafting behavior through team reflexivity, while such behavior is inhibited through team obsessive work passion. Moreover, responsible leadership positively moderates the link between team illegitimate tasks and team reflexivity, thereby strengthening the positive indirect effect via team reflexivity. In addition, responsible leadership negatively moderates the relationship between team illegitimate tasks and team obsessive work passion, thereby weakening the negative mediating effect of team obsessive work passion.