The Environmental Career Worker Training Program (ECWTP) is a comprehensive community-based program designed to increase the number of disadvantaged and underrepresented minority workers in areas such as environmental restoration, construction, and emergency response. Through a consortium of community-based partners, the ECWTP provides pre-employment trainings, certifications, and placements for minority workers in four urban areas across the United States. A utilization-focused participatory evaluation process was created to assess effectiveness and impact of the ECWTPs. Direct comparisons across communities for 15 years were conducted. Results demonstrated that, overall, ECWTPs were highly effective and meaningfully impacted workers’ training-related outcomes. Best practices for programs targeted at training and development of minority workers were also identified. Implications of the role of longitudinal evaluations in providing much needed evidence to strengthen effectiveness and impact of community-based worker training programs and guide related workforce development policy will be discussed.