People who have served time in US prisons and jails have high rates of undiagnosed chronic and infectious diseases, behavioral health conditions, and trauma. Because a large portion of this population are young men—a demographic previously underrepresented in Medicaid rolls—who have been uninsured, Medicaid payers and the managed care plans they contract with have little experience serving this population. To meet the Affordable Care Act’s policy objectives of cost-efficient and effective care through improved and expanded access, health plans need to understand the epidemiology and care-seeking patterns of this population. Plans also need to develop outreach, communications, and engagement strategies and create service models designed to address these individuals’ health care needs. Corrections departments and health plans should exchange information about the medical histories of people entering and leaving prisons and jails, promote models of peer support, and advocate for suspension rather than termination of Medicaid benefits during incarceration, so inmates can quickly regain coverage once they are released.