This contribution builds on the RTD project: The construction of the professional identity of primary school teachers during initial training and the first years at work (MIMECO-EDU2010-20852-C02-01). The main aim of this research is to describe, analyse and interpret the notions, representations and experiences related to the professional identity of primary school teachers in their first working years. The development of nine micro-ethnographies and nine focus groups with more than fifty primary school teachers allowed us to glimpse the continuities and discontinuities between their college learning and their performance as teachers. Our research reveals that novice teachers are confronted with a set of complex tasks for which they feel ill-prepared. In teachers’ readiness to understand the need to go on learning, not only throughout their professional life, but also from and in every situation they happen to be immersed, their biographical background is of great importance. This background can be substantially enriched or otherwise by the initial and in-service professional development and the first teaching experience. The first calls for the need to review in both practice and theory what it means to learn and teach in contemporary society. The second shows the importance of mentoring programs at school level.