In the Chilean educational context emerges a new policy as a system of professional teacher development called the New Teaching Career Law which will be implemented in 2017. This study aims to investigate from the perspective of school principals (n = 173), the impact of the organizational, relational, and individual dynamics of the New Teaching Career Law. The study employed a mixed-method research design using a descriptive-exploratory approach. The results of this study suggest that the process of teacher sorting considers the following points the most important elements in evaluating a teacher's performance: experience, continuous professional development, and results of the teacher evaluation portfolio. However, principals do express doubt regarding the relationship between the categorization obtained by teachers and the effectiveness of them in the school context.