Employing comparative historical method, this study provides an account of reforms and policies in teacher education from 1970s to the present in Alberta, Canada. In particular, this article tracks how teacher professionalism has been conceptualized and enacts over different historical periods in Alberta, and reveals that teacher professionalism, as a socially constructed concept, has taken on different interpretations from "de-professionalism" to "re-professionalism" in Canada historical contexts. Alberta's teacher education policy has been usually used as a dynamic instrument to shape the paradigms of the concept of teacher professionalism. This analysis has also supported the claim that government-led teacher education reform has been accorded the key political significance in Canada. As a whole, the teacher education reform in Alberta area provides a useful concrete understanding and offers international lessons outside of Canada in how historical context influences the reform of teacher professional development.