Traumatic brain injury (TBI) can have lasting physical, cognitive, and emotional health effects that extend well beyond the initial event. In March 2025, the National Academies' Forum on Traumatic Brain Injury convened a workshop to explore TBI as a chronic condition and to identify opportunities to improve lifelong care.Participants examined evidence supporting the classification of TBI as a chronic condition, explored the biological mechanisms that drive long-term outcomes, and discussed the complex comorbidities that can persist or emerge years after injury. Lived experience perspectives shared throughout the workshop underscored the human impact of these issues and the importance of sustained, multidisciplinary support for recovery and well-being. This Proceedings of a Workshop summarizes presentations and discussions from the workshop.