Karen E. Johnson is Kirby Professor Emerita of Language Learning and Applied Linguistics at Penn State. Her scholarship has been devoted to building theory and conducting research on L2 teacher cognition within and for the field of L2 teacher education. Grounded in a Vygotskian sociocultural ‘theory of mind’, her scholarship centers on understanding the learning of L2 teaching, the activity of L2 teaching, and the practices of L2 teacher education. She has accomplished this by empirically documenting the dialogic mediation that emerges inside the practices of L2 teacher education, tracing L2 teacher development as it is unfolding, and detailing the consequences of these interactions on the ways in which L2 teachers begin to think about and attempt to enact their instructional practices with L2 students in the socially situated institutions in which they live and work. Additionally, she has argued that the transformative power of teachers engaging in narrative activities lies in its ability to ignite cognitive processes that can foster L2 teacher professional development and, as a result, critical to the design, enactment, and assessment of the consequences of L2 teacher education. She has published ten scholarly books, the most recent edited collection: Transformative L2 Teacher Innovations: Insights from Vygotskian Sociocultural Theory (2025, Routledge) with Paula R. Golombek and Jacob Rieker. She taught courses in the MA TESL and the Ph.D. in Applied Linguistics degree programs.