Global mental health expertise favors biomedical explanations of mental disorders that conceive such disorders as stable entities, which can be diagnosed according to universal categories. Following this logic, universal and standardized solutions can also be applied throughout the world, regardless of context. Despite its assumptions and data being contested within the field of psychiatry itself, global mental health expertise has been highly stable. How is such expertise produced? Through what mechanisms are its products, such as reports, studies, or numbers, made and replicated? The article proposes a model of expertise production in global governance that discloses specific mechanisms of circularity and exclusivity in knowledge-making processes, which result in the circular and exclusive character of expertise itself. These include the circulation of profesionals and data across spheres and organizations, as well as the role played by several sites such as boundary expert groups, influential research clusters, and “policy-scientific” journals, which operate as powerful centers of knowledge production at the intersection of the policy, scientific or private spheres. Such sites not only act as loci where people's circulation operates at its best but also as autonomous mechanisms that produce, cement, and perpetuate the circularity and exclusivity of expertise beyond the role of specific individuals.