Transformative learning in teacher education qualitatively changes future teachers' meaning systems of learning, teaching, and education. In this study, I explored transformative learning in Finnish class teacher education. Data were collected by observing student teachers over two academic years. Data also contains writings that student teachers produced during that period. A phenomenological analysis focused on the general characteristics of the transformative way of becoming a teacher and identified a process consisting of four phases: starting point, crack, ambivalence, and transformation. A hermeneutic analysis was used to interpret how the process occurred in practice. The results suggest a long and ambivalent process, which challenges educational policy discourses that emphasize efficiency and speed.