This longitudinal case study follows one high school English teacher's path of concept development over a two-year period encompassing her student teaching and first year of full-time teaching, both at the same rural school in the southeastern United States. The authors use a sociocultural theoretical framework emerging from the work of Vygotsky to focus on the construction of activity settings and the ways in which settings help to shape concept development. In particular, the analysis finds the teacher drawing on apparently inconsistent pedagogical traditions and their associated mediational tools: one centered on a teacher's authoritarian control of the curriculum and adherence to formal properties of texts and one centered on students' interests and their agency in learning. (Contains 1 table.)