The professional growth of a teacher student is one the most important themes and subjects of teacher education. Therefore, it is important to make the teacher students’ development process conscious and visible during their studies. In this research, the Professional Growth Path model is built into an eighteenmonth teacher education program. The path model is divided into four stages (I-, You-, We-, and They). Each stage includes a thematic writing prompt appropriate to the stage. The goal of the research was to observe and analyze how the Professional Growth Path model supports teacher students’ development into teachers during their program. This case study research data were collected from a group of fourteen teacher students in a professional teacher education program at one university of a applied sciences in the province of Häme during the school year of 2010- 2011 academic year. The research data consist of fifty-six learning journals, which the students of the teacher student group wrote at different stages of the path model. The data were analyzed using data-based content analysis. The research results show the multi-faceted and personal character of teacher students’ growth into their future profession. The growth to become a teacher happens in a mosaic pattern: students´ studies have much in common, but the end result is still very personal. According to this research, the support of the group in one´s development into a teacher and growth as a human is crucially important. The results indicate that, positive, listening, and respectful attitude by the teacher educator towards the teacher students at the beginning of the program and the careful formation of the new group is a significant factor, the effects of which extend to the end of the program. The implementation of the Professional Growth Path model in teacher education has received positive feedback. In particular, the thematic writing prompts in the various stages of the path model have made the professional growth process of each individual student visible.