The American healthcare system has several types of providers, leading to plethora of minisystems. Working with each of these systems provides specific issues of definition, training and delivery of services. In spite of large proportion of the gross domestic product (GDP) being devoted to healthcare delivery, approximately one-sixth of the population is uninsured and has access only to emergency treatments. This chapter provides a historical account of development of the healthcare system in the United States and the role of various reports and organizations in defining medical professionalism. Changes in organized medicine in response to the demands of society and changing public expectations have led to revisit the components of medical professionalism. The chapter focuses on the broad aspect of medical professionalism. It reviews how medical professionalism has evolved to its present state in the United States and makes recommendations for its ongoing survival.