Partnering with youth and families involved in the juvenile justice system can promote positive youth outcomes and help youth avoid further system involvement. In this brief, we describe findings from a developmental evaluation of the Annie E. Casey Foundation’s expansion of the Juvenile Detention Alternative Initiative® to the deep end of the juvenile justice system. Deep-end reform aims to safely and significantly reduce the use of out-of-home placements for youth, especially youth of color, in juvenile courts. We describe how select jurisdictions engaged youth and families through reform efforts. We also outline the supports that facilitated the meaningful involvement of youth and families. This brief supplements the information presented in Keeping Youth Out of the Deep End of the Justice System: A Developmental Evaluation Overview of the Annie E. Casey Foundation’s Deep-End Reform, which provides an overview of the evaluation of the deep-end reform and its findings.