Though the positive association between well-being and professional identity among employees is well-document, the internal mechanism underlying this association is known little. Guided by self-determination theory (SDT) and the job demands-resources (JD-R) model, this study examined the roles of job crafting and work engagement in mediating the association between professional identity and workplace well-being. We surveyed 2090 teachers (including Primary, Middle, and High School teachers) ( M age = 39.42 years; SD = 8.72). Teachers completed a series of questionnaires, such as the Teachers’ Professional Identity Scale, Employee’s Workplace Well-being Scale, Job Crafting Scale, and Utrecht Work Engagement Scale. We controlled age, teaching age, and gender covariates to get conservative predictions. Multiple mediation analyses were utilized in this study to prove that: (a) professional identity was positively linked to workplace well-being; (b) both job crafting and work engagement take mediator roles in associating the relationships between professional identity and workplace well-being; and (c) a serial indirect pathway (professional identity → job crafting → work engagement → workplace well-being) emerged. These findings explore the factors that affect well-being and point to potential ways in enhancing teachers’ workplace well-being even when the task is severe.