The concept of the Digital Commons encompasses diverse digital systems and solutions developed and maintained by groups rather than individuals or single entities. These groups coordinate through peer collaboration instead of pricing or subordination. Digital commons often start as small community projects but can scale into infrastructures, attracting large contributor bases and enabling global applications. Infrastructures, recognized for their economic and social functions, provide a generative input into various activities, though their overall impact remains challenging to measure. The free market policies of the 1990s created a private and platform-driven digital environment. However, increasing demand for public digital infrastructures has led to new policy debates positioning the state as an “entrepreneurial state” promoting openness and “generative interoperability.” These debates focus on the diverse public functions and derivative uses digital infrastructures should support. Foundations for digital services and transactions, critical internet stack components, public spaces, and shared production platforms are seen as vital generative inputs for economic and social well-being. Policymakers propose various forms of public ownership to ensure these infrastructures’ public character and societal benefits, often incorporating Digital Commons. This paper reviews existing literature, emphasizing on current global debates and typologies of public digital infrastructures. Through five case studies, the paper highlights approaches addressing infrastructure gaps and deepens the understanding of how Digital Commons can sustain and enhance various forms of public digital infrastructures. The case studies demonstrate the nuanced approach to public digital infrastructures adopted by policymakers, leveraging the many Digital Commons and public ownership to maximize societal benefits and ensure inclusive, open, and interoperable ecosystems. The ZenDiS and scikit-learn cases illustrate ecosystem strategies aimed at strengthening open source software connecting information systems and devices. Decidim, created by the city of Barcelona, showcases partnerships providing alternative spaces for online public speech and debate. DHIS2, used by many governments for health information management, exemplifies collectively managed and produced digital infrastructures, facilitating resource and capacity mutualization. Finally, the European Open Science Cloud (EOSC) is a unique example of a pan-European attempt to build a shared infrastructure with a community of researchers, not only redefining the tools and processes used by researchers, but also developing an infrastructure embedded in the values and principles of Open Science. These case studies provide insights into the conditions necessary for Digital Commons to provide infrastructure, particularly regarding long-term funding, which communities struggle to secure. They also highlight the diverse relationships between public institutions and Digital Commons, impacting Digital Commons’ governance.