This case study examines the classroom instruction of an experienced teacher in an elementary school where the principal supported teachers’ autonomy and authority over curriculum and instruction. The results demonstrate how teachers’ professional discretion is being minimized in subtle yet consequential ways amid high-stakes testing, even in subject areas not tested by the state. Constrained professionalism represents a new situation in which teachers retain autonomy in classroom practices. However, their decisions are significantly circumscribed by contextual pressures and time demands that devalue their professional experience, judgment, and expertise.