This thesis comprises three separate studies that together explore how Swedish student teachers construct or produce professional identity in interaction while navigating different institutional and professional instances of teacher education. As a discourse analytical contribution to research on teacher identity, the main theoretical framework is mediated discourse theory (e.g. Scollon 2001a). For data construction and analysis in the studies, different parts of the two related methodologies of nexus analysis (Scollon & Scollon 2004) and multimodal (inter)action analysis (Norris 2011) are employed. Constructed through an ethnographic approach, the interactional data consist of audio and video recordings of interaction in instances from three different components of a Swedish teacher education program: a rhetoric course, a bachelor thesis course in history and teaching placement. Furthermore, the data include observational field notes and interviews, as well as resources used by the participants, primarily written texts. Taking place early on in teacher education, Study I focuses on student teachers performing oral presentations under the fictitious presumption that they are speaking as teachers. Employing the notion of communicative project (Linell 1998), the empirical aim of the study is to shed light on how student teachers manage institutional affordances and constraints affecting interactional role shifts from student teacher to teacher. In Study II, three student teachers are writing their bachelor theses in the subject of history, and the study focuses on the interactional production of teacher identity of one of the students during seminars. While partly being a methodological study, Study II empirically explores how student teachers interactionally relate to their future profession in an academic disciplinary setting, highlighting which actors and institutions are involved in the production of professional identity. Finally, Study III concentrates on a student teacher during his final teaching placement. Focusing on previous experiences resemiotized as stories, Study III highlights how discourse re-emerging from the historical body (Nishida 1958) can be used in interaction in producing identity. The results suggest that the production of teacher identity by the student teachers is a co-operative and communicative task, where previous experiences as well as an anticipatory perspective on the teaching profession are important features. The three studies identify different resources that can be used and adapted by students to suit different purposes in professional identity production, described as textual resources, embodied resources, and narrative resources. In turn, the different uses of such resources motivate the need for studying identity in interaction with an approach where ethnographic and sociocultural knowledge is part of the analysis. The creative use of resources in identity production highlights that students use knowledge and experience linked to academic and professional as well as everyday discourse in producing professional identity. Presuming an interest in opportunities for student teachers to develop professional identity during their education, it appears fruitful to reflect upon how potential resources are designed and implemented in teacher education, and how institutional affordances and constraints affect the possibilities of using them.