With the constructivist view of learning as a conceptual lens, this paper examines student teachers' professional learning in initial teacher education (ITE). A mixed-method study was conducted with student teachers of a Bachelor of Education Programme in Hong Kong. The quantitative element of the study reveals that student teachers held a constructivist conception of teaching and learning, and this conception was related to their learning experiences in different aspects of the ITE Programme, including the core components of the formal curriculum, informal and hidden curriculum, field experience and non-local experiences. The qualitative findings added further understanding of the dynamics and complexities of student teachers' development of the constructivist conception through learning in ITE coursework and fieldwork as well as their active construction of the professional artistry of teaching. Implications for enhancing student teachers' professional learning in ITE in support of the constructivist conception of teaching and learning are discussed. (Contains 3 tables.)