Maintaining high levels of positive mental health, i.e. to flourish, reduces the risk of developing mental illness up to eight times, compared to having low positive mental health over ten years. Less is known about the longitudinal impact of levels of flourishing on mental illness recovery. This study investigated if longitudinal change in positive mental health was a predictor of mental illness recovery in a cohort group. Using data from a representative American population sample (n=1,723), logistic regression was used to estimate the Odds Ratio that individuals diagnosed with a mental illness in 1995 would have recovered in 2005 based on whether their level of positive mental health changed over a 10-year period. Change in positive mental health was strongly predictive of recovery of mental illness. Individuals who maintained or gained the highest levels of positive mental health were more than 27 and 7 times, respectively, more likely to recover when compared to those who maintained the lowest level of positive mental health. This study suggests that positive mental health may be an important resource for individuals to recover from mental illness, highlighting the need to include positive mental health assessment and interventions into mental health care systems.