This dissertation study employed participatory methods of qualitative inquiry to understand how, in the setting of the North Carolina piedmont, a district-initiated multi-tiered professional development program mediated mainstream elementary school teachers' professional subjectivities in relation to culturally and linguistically complex classrooms. Bringing a Vygotskian framework for understanding the cultural nature of human development (Portes & Salas, 2011) to participatory fieldwork (Emerson, Fretz, & Shaw, 1995; Wolcott, 2009), the study sought to understand what a cohort of elementary educators took away from a multicultural in-service teacher education program sponsored by a local university and how, five years later, the experience of that in-service learning mediated their current professional subjectivities with linguistically diverse classrooms. Findings included the potential need for in-service training models aimed at fostering teacher capacity with student diversity to reexamine its assumptions about the "funds of knowledge" teachers potentially bring to staff development. Likewise, the study suggested that in-service teacher learning is mediated by the lived experiences of the participants as well as the local contexts and circumstances of schools and schooling.