This article describes the methodology, recruitment, participant characteristics, and sustained, intensive stakeholder engagement for Project ACE (Achieving control, Connecting resources, Empowering families). Project ACE is a randomized controlled trial of children and youth ages 8–16 with type 1 diabetes evaluating the impact of tailored self-management resources on hemoglobin A1c (A1c) and quality of life (QOL). Despite strong evidence that controlling A1c reduces long-term complications, <25% of US youth with type 1 diabetes meet A1c targets. Many interventions are efficacious in improving A1c and QOL for these youth, whose families often struggle with the substantial demands of the treatment regimen. However, most such interventions are ineffective in the real world due to lack of uptake by families and limited healthcare system resources. Project ACE is a multi-site trial designed to improve diabetes outcomes by tailoring existing, evidence-based interventions to meet families’ needs and preferences. We hypothesize that this family-centered approach will result in better A1c and QOL than usual care. Project ACE has recruited and randomized 214 eligible 8–16 year old youth and their parents. The 9-month intervention consisted of 4 group sessions tailored to families’ self-management barriers as identified by a validated instrument. Outcomes including A1c and QOL for parents and youth will be assessed for 1 year after the intervention. Stakeholder engagement was used to enhance this trial’s recruitment, retention and integration into routine clinical care. Findings will inform implementation and dissemination of family-centered approaches to address self-management barriers.