Youth who receive Supplemental Security Income (SSI) benefits experience disparate educational, employment, and economic outcomes when compared to youth with disabilities who do not receive these entitlements. Promoting the Readiness of Minors in Supplemental Security Income (PROMISE) was a 6-year national research demonstration project that designed, implemented, and evaluated interventions that led to more successful postschool outcomes for youth SSI recipients ages 14 to 16. Although prior research demonstrations have been conducted testing the combination of case management with other services and supports with SSI populations, research on the taxonomy of those case management strategies considered most effective in supporting positive postschool outcomes is very limited. This article presents a comprehensive taxonomy of case management that provides a common frame of reference for future research on effective case management strategies and translation to practice by discussing implications for policy, practice, and further research when supporting successful postschool outcomes of youth SSI recipients.