BACKGROUND: Career calling, professional identity and the need for achievement are believed to affect the students' learning engagement and effect. However, their regulatory relationship with medical students remains unclear. METHODS: Our study surveyed 1250 medical students through a questionnaire, and the correlation of the study variables was analysed. Harman's Single-Factor test was performed on the data to rule out significant common method biases. The mediation effect was determined using the percentile Bootstrap method with deviation correction. RESULTS: Career calling was positively correlated with professional identity (r = 0.51, p <
0.001) and positively correlated with the need for achievement (r = 0.49, p <
0.001). Learning engagement was positively correlated with professional identity (r = 0.56, p <
0.001) and positively correlated with the need for achievement (r = 0.55, p <
0.001). Professional identity was positively correlated with the need for achievement (r = 0.51, p <
0.001). In addition, professional identity plays a mediating role in the relationship between career calling and learning engagement (β = 0.36, p <
0.001). Additionally, the need for achievement influences how career calling affects learning engagement through professional identity (β = -0.06, p <
0.001). CONCLUSIONS: Career calling, professional identity and the need for achievement were positively associated with learning engagement in medical students. Professional identity and the need for achievement act as intermediaries between career calling and learning engagement. This study found that strengthening the professional guidance of medical students and enhancing their sense of professional mission could promote their acceptance and identification of their major, enhance their professional identity, create a positive professional atmosphere, and improve learning engagement.