Permanent supportive housing (PSH) is an evidence-based health intervention for persons experiencing homelessness, but the impact of individual mechanisms within this intervention on health requires further research. This study examines the longitudinal impact of the mechanism of supportive housing within a peer-delivered PSH model on overall health and mental health (as measured by psychological distress and self-report of bothersome symptoms) outcomes in an ethnically diverse population. The 237 participants in the study included persons who were homeless or at risk of homelessness and who also had been diagnosed with a serious mental illness. Sixty-one percent of all participants received supportive housing. All 3 outcomes were significantly associated with quality of life indicators, recovery, and social connectedness. In addition, overall health was significantly associated with employment, age, and psychological distress. Psychological distress was associated with gender, type of housing, and history of violence or trauma. Experiencing bothersome symptoms was associated with drug use, history of violence or trauma, and psychological distress. Longitudinal models of these 3 outcomes showed that supportive housing was significantly associated with good to excellent health 6 months after baseline (odds ratio = 3.11, 95% confidence interval [1.12, 8.66]). The models also demonstrated that the supportive housing and comparison groups experienced decreased psychological distress after baseline. The results of this study demonstrate the importance of supportive housing within the context of PSH, particularly for the overall health of participants, and the positive overall impact of PSH on mental health in a diverse population.