Despite clinical guidelines for the management of traumatic brain injury (TBI), evidence-based rehabilitation programmes and large-scale studies evaluating rehabilitation provision and outcomes remain limited. This study aimed to (1) describe rehabilitation services delivered to patients admitted to the intensive care unit (ICU) after TBI, (2) examine associations between rehabilitation support and functional outcome, emotional distress, and TBI-specific health-related quality of life (HRQoL) at 12 months post-injury, and (3) assess the stability of outcomes at 3, 6, and 12 months post-injury. Data were obtained from the CENTER-TBI study. Participants were adults (≥18 years) admitted to the ICU who reported rehabilitation use and completed follow-up assessments. Functional outcome was assessed using the Glasgow Outcome Scale–Extended (GOSE), emotional distress using the Patient Health Questionnaire (PHQ-9) and the Generalized Anxiety Disorder scale (GAD-7), and HRQoL using the Quality of Life after Brain Injury–Overall Scale (QOLIBRI-OS). The study included 661 patients (72.3% male; mean age 46.7 years). At 12-month post-injury, 87% achieved favorable recovery (GOSE 5–8), with mild depressive symptoms, minimal anxiety, and a mean QOLIBRI-OS score of 65.7. Rehabilitation provision increased from 30.6% at 3 months to 51.3% at 12 months. Early rehabilitation was most common among patients with mild TBI, while rehabilitation provision for those with moderate and severe TBI increased over time. Nevertheless, approximately half of patients with moderate-to-severe TBI did not receive rehabilitation within the first-year post-injury. Delayed initiation of rehabilitation, older age, lower education, unemployment, greater injury severity, and road traffic-related injuries were associated with poorer functional outcomes and lower HRQoL. Pre-injury psychiatric disorders predicted higher emotional distress. Functional recovery and HRQoL improved over time, whereas emotional distress remained relatively stable. Despite increasing rehabilitation provision, substantial gaps in access persist, particularly for patients with moderate and severe TBI. Early and well-coordinated rehabilitation remains essential to optimize recovery and long-term quality of life after TBI.