This research explores and deepens our understanding of an element of arts infrastructure in the United States: the arts incubator, an organizational form or programmatic initiative that exists at the intersection of artistic production, entrepreneurship, and public policy. The study is a qualitative cross-case analysis of four arts incubators of different types: Arlington Arts Incubator, Intersection for the Arts, Center for Cultural Innovation, and Mighty Tieton, situated within the context of the literature of arts incubators, business incubator evaluation, and a theoretical framework for understanding entrepreneurship in the US arts and culture sector.The research opens the black box of incubator operations to find that arts incubators create value for client artists and arts organizations both through direct service provision and indirect echo effects but that the provision of value to communities or systems is attenuated and largely undocumented. Arts incubators, like many small arts organizations, tend to look retrospectively at outputs rather than at the processes that convert inputs to tangible impacts, or means into ends. This is an issue not relegated only to the arts and culture sector; business incubators share some of these tendencies. Despite these issues, arts incubators remain a potentially impactful tool of cultural policy if their processes and activities align with their strategic goals and those processes and activities are assessed formatively and summatively.ii