The World Health Organization (WHO) was born as a normative agency and has looked to global health law to structure collective action to realize global health with justice. Framed by its constitutional authority to act as the directing and coordinating authority on international health, WHO has long been seen as the central actor in the development and implementation of global health law. However, WHO has faced challenges in advancing law to prevent disease and promote health over the past 75 years, with global health law constrained by new health actors, shifting normative frameworks, and soft law diplomacy. These challenges were exacerbated amid the COVID-19 pandemic, as states neglected international legal commitments in national health responses. Yet, global health law reforms are now underway to strengthen WHO governance, signaling a return to lawmaking for global health. Looking back on WHO’s 75th anniversary, this article examines the central importance of global health law under WHO governance, reviewing the past successes, missed opportunities, and future hopes for WHO. For WHO to meet its constitutional authority to become the normative agency it was born to be, we offer five proposals to reestablish a WHO fit for purpose: normative instruments, equity and human rights mainstreaming, sustainable financing, One Health, and good governance. Drawing from past struggles, these reforms will require further efforts to revitalize hard law authorities in global health, strengthen WHO leadership across the global governance landscape, uphold equity and rights at the center of global health law, and expand negotiations in global health diplomacy.