The role of institutionalized philanthropy is a blind spot in Canadian scholarship on public management. This article identifies five ways in which private “family” foundations add value to public management: through their roles in grantmaking; advancing social innovation; field building; shaping ideas; and advocating for policy and social change. An assessment of how well Canada's largest family foundations—those holding more than $100 million in assets—perform on each of these indicates they are not realizing their potential and need to be more attentive to their claim to public legitimacy. Equally, governments need to be more creative in how they work with the philanthropic sector.