Facilitating classroom discussion requires preparation and improvisation. How might learning improvisational theatre affect teachers' verbal moves while facilitating discussion? This article explores this question through a single-subject case study of a high school history teacher who took a 10-week improv course. Data sources include observations of classroom discussion, interviews, and field notes and artifacts from observed discussions and improv sessions. Findings suggest that discussions changed, the teacher did not know he changed, and he may have made these shifts unconsciously based on the conceptual overlaps he saw between improv principles and the intellectual work of discussing, the opportunities the course gave him to exercise presence and the "Yes, and" principle of improv, and his participation in and appreciation of the improv instructor's facilitation style.