Increased dissemination of the CDC's Diabetes Prevention Program (DPP) is imperative to reduce type 2 diabetes. Due to its nationwide reach and mission to improve health, Cooperative Extension (Extension) is poised to be a sustainable DPP delivery system. However, research evaluating DPP implementation in Extension remains scant. Extension professionals delivered the DPP in a single-arm hybrid type II effectiveness-implementation study. Semi-structured interviews with Extension professionals were conducted at three time points. The Consolidated Framework for Implementation Research (CFIR) guided interview coding and analysis. Constructs were rated for magnitude and valence and evaluated as facilitators or barriers of RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) outcomes. The program reached 119 participants, was adopted by 92% (n = 12/13) of trained Extension professionals and was implemented according to CDC standards: all programs exceeded the minimum 22-session requirement (26 ± 2 sessions). The program was effective in achieving weight loss (5.0 ± 5.2%) and physical activity (179 ± 122 min/week) goals. At post-intervention, eight professionals (67%) had begun or planned to maintain the intervention within the next 6 months. Several facilitators were identified, including Extension leadership structure, organizational compatibility, and technical assistance calls. Limited time to recruit participants was the primary barrier. Positive RE-AIM outcomes, facilitated by contextual factors, indicate Extension is an effective and sustainable DPP delivery system. Extension and other DPP implementers should plan strategies that promote communication, the program's evidence-base, recruitment time, and resource access. Researchers should explore DPP implementation in real-world settings to determine overall and setting-specific best practices, promote intervention uptake, and reduce diabetes.