Residents must develop knowledge, skills, and attitudes to handle a rapidly developing clinical environment. To address this need, adaptive expertise has been suggested as an important framework for health professions education. However, research has yet to explore the relationship between workplace learning and adaptive expertise. This study sought to investigate how clinical supervision might support the development of adaptive expertise. The present study used a focused ethnography in two emergency departments. We observed 75 supervising situations with the 27 residents resulting in 116 pages of field notes. The majority of supervision was provided by senior physicians, but also included other healthcare professionals. We found that supervision could serve two purposes: closure and discovery. Supervision aimed at discovery included practices that reflected instructional approaches said to promote adaptive expertise, such as productive struggle. Supervision aimed at closure-included practices with instructional approaches deemed important for efficient and safe patient care, such as verifying information. Our results suggest that supervision is a shared practice and responsibility. We argue that setting and aligning expectations before engaging in supervision is important. Furthermore, results demonstrated that supervision was a dynamic process, shifting between both orientations, and that supervision aimed at discovery could be an an appropriate mode of supervision, even in the most demanding clinical situations.