Digital library infrastructures must not simply work. They must also manifest the core principles of libraries and archives. Since 2014, the Institute of Museum and Library Services (IMLS) has engaged with stakeholders from diverse library communities to consider collaborative approaches to building digital library tools and services. The “national digital platform” for libraries, archives, and museums is the framework that resulted from these dialogs. One key feature of the national digital platform (NDP) is the anchoring of core library principles within the development of digital tools and services. This essay explores how NDP-funded projects enact library principles as part of the national framework.