The authors propose that professionalism, rather than being left to the chance that students will model themselves on ideal physicians or somehow be permeable to other elements of professionalism, is fostered by students' engagement with significant, integrated experiences with certain kinds of content. Like clinical reasoning, which cannot occur in a vacuum but must be built on particular knowledge, methods, and the development of skills, professionalism cannot flourish without its necessary basis of knowledge, methods, and skills. The authors present the need for an intellectual widening of the medical curriculum, so that students acquire not only the necessary tools of scientific and clinical knowledge, methods, and skills but also other relevant tools for professional development that can be provided only by particular knowledge, methods, and skills outside bioscience domains. Medical students have little opportunity to engage any body of knowledge not gained through bioscientific/empirical methods. Yet other bodies of knowledge-philosophy, sociology, literature, spirituality, and aesthetics are often the ones where compassion, communication, and social responsibility are addressed, illuminated, practiced, and learned. To educate broadly educated physicians who develop professionalism throughout their education and their careers requires a full-spectrum curriculum and the processes to support it. The authors sketch the ways in which admission, the curriculum (particularly promoting a sociologic consciousness, interdisciplinary thinking, and understanding of the economic/ political dimensions of health care), and assessment and licensure would function.