(1) To determine the proportion of participants admitted to supported community living (SCL) programs over the course of 5 years who improve, decline, or maintain functioning and community integration and (2) to examine the associations of time since injury, time in program, and age to their functional trajectory. Data from SCL programs serving individuals with acquired brain injury (ABI). 104 individuals with traumatic brain injury (TBI), stroke, or other ABI. Sex, age, time since injury, Mayo-Portland Adaptability Inventory (4th edition; MPAI-4). Retrospective analyses of MPAI-4 total and MPAI-4 indices using Linear Mixed Models (LMM) of Rasch-derived T-scores from admission to 5 years into service delivery. MPAI-4total, index, and subscale scores for yearly intervals of SCL services from admission to 5years showed a high degree of stability in function (defined using the standard error of measurement (SEM) for the MPAI-4, defined as change≥3T-score points) with all intervals showing at least 89% of patients with improved scores or no change. The rate of change over time did not significantly vary by time since injury, time in the program, or age. The expectations for services in the SCL portion of the care continuum for ABI are unique. Unlike intensive rehabilitation programs which focus on improvement often earlier in the course of recovery, the goal of SCL services is sustained functioning over the long term. Analyses reported here indicate this can be achieved for at least 5years, potentially mitigating the increased risk for rehospitalization and increased care needs in the ABI population. This study highlights a key finding of MPAI-4 stability within these understudied brain injury service lines. Additional exploration of comorbidities and more nuanced delineation of diagnostic information could further clarify factors influencing outcome stability over time.