The Family First Prevention Services Act (FFPSA) allows states to use federal Title IV-E funds to provide time-limited, clinically appropriate use of congregate care, including Qualified Residential Treatment Programs (QRTPs), for youth in foster care. October 1, 2021 marked the deadline for states to begin implementing these FFPSA congregate care reforms. From June to September 2022, we conducted a mixed-methods study to obtain a baseline understanding of implementation barriers, successes, and recommendations to inform congregate care policy and practice. We fielded a national survey with state child welfare agency directors and conducted focus groups with youth with QRTP experiences, child welfare agency administrators, and QRTP executive leaders. We integrated a descriptive analysis of survey data with focus group themes to summarize state implementation progress. A total of 47 states (90%) responded to the survey. Most states reported ongoing congregate care reforms aligned with FFPSA, reducing the use of congregate care and increasing kinship foster care. QRTPs have become the primary congregate care setting. Top implementation barriers concerned workforce resource and capacity constraints, funding, and access to therapeutic foster care models and foster families. Focus group themes converged on the lack of tailored treatment, quality staff, coordinated aftercare, and a need for QRTP outcome evidence. Early implementation lessons of FFPSA congregate care reforms call for additional funding and technical assistance, oversight of congregate care, professionalization and investment in QRTP staff, youth advisory boards to promote youth-driven treatment, and performance- and outcome-based monitoring of QRTPs.