 Jonsen was a pioneer in the practice of "clinical ethics", in which an ethicist serves as a consultant to those making ethical decisions about appropriate care of patients.Jonsen joined John Fletcher as founders of the Society for Clinical Ethics (SBC), which later merged with the Society for Health and Human Values (SHHV) and the American Association of Bioethics (AAB) to form the American Society for Bioethics and Humanities (ASBH) in 1998.In 1987, Jonsen assumed the chairmanship of the Department of Medical History and Ethics, School of Medicine, University of Washington.