This randomized controlled trial examined benefits of adding active health promotion to basic primary care (BPC) services for SMI adults. It compared BPC with BPC plus wellness training (WT), a 12 months intervention promoting individual skills in self-management. Three hundred nine participants enrolled during short-term residential treatment completed baseline assessments and were assigned to treatment groups, before discharge. Outcomes of perceived health status (SF-36), global assessment of function, and ratings of self-efficacy were assessed at follow-up interviews at 6, 12, and 18 months. The intent-to-treat analysis employed multilevel regression to examine differences by group on outcomes across time, controlling for health related covariates. The WT group showed significantly better outcomes on the SF-36 physical functioning and general health scales. Findings affirm ability of SMI adults to benefit from active health promotion.