The person of the teacher is an essential element in what constitutes professional teaching and therefore needs careful conceptualisation. In this article the author argues for this central thesis, presenting a wrap up of his theoretical and empirical work on the issue over the past decade. These studies have been inspired--both conceptually and methodologically--by teacher thinking-research as well as the narrative-biographical approach to teaching and teacher development. The result is an empirically grounded conceptual framework on teacher development and teacher professionalism. Central concepts are "professional self-understanding" and "subjective educational theory" as components of the personal interpretative framework every individual teacher develops throughout his/her career. This personal framework results from the reflective and meaningful interactions between the individual teacher and the social, cultural and structural working conditions constituting his/her job context(s). As such the framework is the dynamic outcome of an ongoing process of professional learning (development). Furthermore, it is argued, that the particular professionalism or scholarship of teachers is fundamentally characterised by personal commitment and vulnerability, which eventually have consequences for the kind of reflective attitudes and skills professional teachers should master. (Contains 4 notes.)