This study used an experimental design to examine longitudinal changes in subjective quality of life (QoL) among homeless adults with mental illness after assignment to different types of supported housing or to treatment as usual (TAU, no housing or supports through the study). We hypothesized that subjective QoL would improve over time among participants assigned to supported housing as compared to TAU, regardless of the type of supported housing received or participants’ level of need. <i>Methods</i> Participants (n = 497) were stratified by level of need (“high” or “moderate”) and randomly assigned to Housing First (HF) in scattered-site apartments, HF in a congregate setting (high needs only), or TAU. Linear mixed-effects regression was used to model the association between study arm and self-reported QoL at baseline and at 6 and 12 months post-baseline by need level. <i>Results</i> Based on the adjusted overall score on the QoL measure, participants randomized to HF reported significantly greater overall QoL as compared to TAU, regardless of need level or type of supported housing at both 6 and 12 months post-baseline. Scores on the safety and living situation subscales were significantly greater for both high and moderate need participants assigned to supported housing regardless of type at both 6 and 12 months post-baseline as compared to TAU. <i>Conclusions</i> Despite multiple health and social challenges faced by homeless individuals with mental illness, HF in both scattered-site and congregate models results in significantly greater perceived QoL as compared to individuals who do not receive HF even after a relatively short period of time.