The purpose of this article is to present results of an ongoing longitudinal qualitative study that aims to chart the dynamics of professional identity construction of Estonian psychology students over the period that embraces their studies of psychology in a bachelor's program and two years after obtaining a bachelor degree. The construction of an identity is discussed from socio-cultural perspective, and in terms of the semiotic mediation approach. To investigate dynamics in intra-psychological level, the dialogical self theory (Hermans, 1995) was applied. The results show how the Self <> Self and Self <> Other dynamics set up differentiation of inherently inconsistent parts of the Self (“being myself” <> “being a psychologist”), and that the entry into professional role entails inter-individually different linkage of the features of personal culture with different aspects of the expected role of psychologist.