This cross-sectional study investigated the relationship between academic achievement (measured by GPA) and a science-related psychological variable, science identity, in higher education. Specifically, the study examined the mediating role of science identity in the relationship between academic achievement and commitment to a postgraduate career. Data drawn from 309 pre-service teachers were analyzed using structural equation modelling. The results revealed positive relationships between academic achievement, science identity, and postgraduate career commitment. Academic achievement and science identity significantly predicted pre-service teachers' postgraduate career commitments. Furthermore, science identity served as a mediator in the relationship between academic achievement and career commitment. These findings point to the benefits of effective interventions that support the development of science identity in teacher education and development to encourage pre-service and in-service teachers' commitment for postgraduate career. These strategies can foster pre-service and in-service teachers to engage in science-based practices, enhance their scientific competences, gain recognition from their colleagues or educators, and implement science-based practices in their own teaching.