Background <p>Among the available evidence-based interventions targeting dementia family caregivers, there is limited evidence on implementation processes that produce desired outcomes (i.e., reductions in depression and burden) for caregivers, people living with dementia (PLWD), and community-based programs themselves. In a national multi-site hybrid effectiveness trial, we investigated the implementation success and challenges of embedding an evidence-based intervention (ADS Plus) targeting dementia family caregivers whose PLWD was enrolled in an adult day service (ADS).</p> Methods <p>Informed by the Consolidated Framework for Implementation Research, we conducted a directed qualitative content analysis to understand caregiver (<i>n</i> = 15) and staff (<i>n</i> = 14) perceptions of facilitators of and potential barriers to implementation of ADS Plus in nine ADS programs to guide future dissemination efforts.</p> Results <p>Results demonstrated that successful delivery of ADS Plus was achieved through intervention adaptability, personalization, and structure (innovation); responsiveness of ADS Plus to external changes and intervention marketability (outer domain); presence of aligned goals and familiarity (inner setting); involvement of research staff, connections among practitioners, and meeting caregiver needs (individual domain); and understanding caregivers’ needs and addressing staff capacity to take action (implementation process). This adaptability reassures us of the potential to implement ADS Plus in heterogeneous programmatic settings. </p> Conclusion <p>Globally, our results demonstrate that ADS Plus offers a viable community-based solution for supporting dementia family caregivers with high implementation potential for diverse ADS settings.</p> Trial registration <p>ClinicalTrials.gov ID: NCT02927821 (Registration Date 10/7/2016).</p>