Employment is a potential source of stability and opportunity for Americans trying to better their lives after involvement with the criminal justice system. The path to employment can be difficult for this population, however, and the challenges differ depending on age. Adults often enter the justice system with barriers to employment and struggle to reconnect to the labor market after their release from incarceration, due to such factors as limited basic skills and soft skills, employers' reluctance to hire people with criminal records, and difficulty retaining stable employment because of unstable housing, lack of adequate transportation, or mental health problems. Young adults (ages 18 to 24) are developmentally different from adults; therefore, programs that improve outcomes for adults may need to be tailored to address the specific needs of young adults before they show similar results. Disruptions in education due to court involvement early in the lives of young adults can derail future employment opportunities, without appropriate interventions. Both populations need support in connecting to employment after justice system involvement. This issue brief maps the evidence and remaining gaps in the knowledge base on interventions for these groups ahead of a national evaluation of employment-focused reentry programs serving justice-involved adults and young adults.