Research-based practices—psychosocial, behavioral, and public health interventions—have been demonstrated to be effective and often cost-saving treatments, but they can take up to two decades to reach practitioners within the health and human services workforce worldwide. Practitioners often rely on anecdotal evidence and their “practice wisdom” rather than on research, and may thus unintentionally provide less effective or ineffective services. Worldwide, community engagement in research is recommended, particularly in low-resource contexts. However, practitioner involvement has not been adequately explored in its own right as an innovative community-engaged practice that requires a tailored approach. The involvement of practitioners in research has been shown to improve their use of research-based interventions, and thus the quality of care and client outcomes. Nevertheless, the literature is lacking specificity about when and how (that is, using which tasks and procedures) to nurture and develop practitioner–researcher partnerships. This paper offers theoretical and empirical evidence on practitioner–researcher partnerships as an innovation with potential to enhance each phase of the research cycle and improve services, using data from the United States, Brazil, and Spain. Recommendations for partnership development and sustainability are offered, and a case is made for involving practitioners in research in order to advance social justice by amplifying the local relevance of research, increasing the likelihood of dissemination to community settings, and securing the sustainability of research-based interventions in practice settings.