The mechanisms underlying complex brain function and cognition have puzzled us all. Traumatic brain injury (TBI), a brain disorder caused by external forces, provides a unique window to tackle these challenges. From the prevailing perspective of network theory, cognitive function is driven by dynamic interactions between large-scale neural circuits or networks, enabling behavior, while brain dysfunction after TBI is caused by the desynchronized rhythms when the brain network and its supporting system are under attack. However, the current research faces significant challenges in pinpointing the complexity and heterogeneity of TBI. I will lead a multidisciplinary research group to understand brain injury mechanisms from an explicitly integrative perspective and use TBI as a tool to study individual brain phenotypes and recovery, eventually adding to our understanding of brain function mechanisms. We will study various biomechanical and physiological features of the brain that potentially affect individual susceptibility to TBI, heterogeneous mechanisms of injury and potential individualized diagnosis, brain recovery mechanisms, and eventually the controllability of brain function. Success in these aims may ultimately transform our understanding of the TBI mechanisms, will reveal new methods for individualized protection and therapeutic interventions, and will broadly help the scientific community chart a path toward a better understanding of the brain as a multilayer network system.