Each year, more than 10 million people enter US jails, most returning home within a few weeks. Because jails concentrate people with infectious and chronic diseases, substance abuse, and mental health problems, and reentry policies often exacerbate these problems, the experiences of people leaving jail may contribute to health inequities in the low-income communities to which they return. Our study of the experiences in the year after release of 491 adolescent males and 476 adult women returning home from New York City jails shows that both populations have low employment rates and incomes and high rearrest rates. Few received services in jail. However, overall drug use and illegal activity declined significantly in the year after release. Postrelease employment and health insurance were associated with lower rearrest rates and drug use. Public policies on employment, drug treatment, housing, and health care often blocked successful reentry into society from jail, suggesting the need for new policies that support successful reentry into society.