Health advocacy is being formalized as a professional activity for physicians across North America, but the accommodation of this activity into conceptions of daily practice has been controversial and confusing. There appears to be a lack of clarity around what a physician should do as a health advocate and how this should manifest in daily practice. In this article, the authors explore how the medical community has characterized the health advocate role and the roots of the debates regarding its place within training and practice, using the example of the CanMEDS Health Advocate Role. They argue that the confusion might be a result of subsuming two distinct activities, agency and activism, under the rubric of health advocacy. They propose that these activities and their associated skills are sufficiently distinct as to merit separate discussions. Agency involves advancing the health of individual patients ("working the system"), and activism involves advancing the health of communities and populations ("changing the system"). The authors suggest that distinguishing between agency and activism within health advocacy provides opportunities to explore their distinct goals and skill sets in a manner that will advance the debate about health advocacy, a conversation that remains critically important to the medical profession.