The U.S. health care system is undergoing a shift from individual clinical practice toward team-based care. This move toward team-based care requires fresh thinking about clinical leadership and responsibilities to ensure that the unique skills of each clinician are used to provide the best care for the patient as the patient's needs dictate, while the team as a whole must work together to ensure that all aspects of a patient's care are coordinated for the benefit of the patient. In this position paper, the American College of Physicians offers principles, definitions, and examples to dissolve barriers that prevent movement toward dynamic clinical care teams. These principles offer a framework for an evolving, updated approach to health care delivery, providing policy guidance that can be useful to clinical teams in organizing the care processes and clinician responsibilities consistent with professionalism.