The Center for Alternative Sentencing and Employment Services (CASES) will implement the Nathaniel CCBHC, a forensic-specialist CCBHC in Central Harlem serving a focus population of criminal justice-involved youth and adults who have mental illness and co-occurring disorders (CODs). Over the life of the grant term, Nathaniel CCBHC will serve 1,375 clients: 650 in Year 1 and 725 in Year 2, about 80% male, 80% Black or Multiracial, and 35% Latinx, consistent with disparities in criminal justice (CJ) involvement. The focus population includes: 49% with serious mental illness, 55% with high-severity PTSD, 33% with severe substance use disorder, 72% at risk body mass index (BMI), 34% at risk regular smokers, 57% with incarceration experience, 45% with open legal cases in Criminal and Supreme Courts, and 31% homeless. Central Harlem experiences significant disparities in residents' CJ involvement and public health. The neighborhood ranks first in NYC for new HIV diagnoses, and its residents experience high rates of non-fatal assault, psychiatric, and avoidable hospitalization.The Nathaniel CCBHC responds to the risks for premature treatment dropout and poor treatment engagement and other prevalent outcomes among CJ-involved populations with CODs. Co-located in Central Harlem with high-volume Pretrial and Alternative-to-Incarceration (ATI) programs, the CCBHC will provide comprehensive, CJ-specialist outpatient interventions. Targeting CJ-involved persons at elevated risk for poor health and recovery outcomes, the CCBHC will engage consumers in a culturally-competent, risk-responsive, and trauma-informed approach that incorporates mobile, care coordination, and rehabilitation services--addressing a critical community need. The CCBHC envisions the integration of mental health and primary care and the addition of robust substance use disorder (SUD) treatment, mobile 24/7 crisis and outreach services, peer support, case management, and care coordination--guided by CASES' CJ-specialist approach. The program will a) provide rapid access and engagement in comprehensive integrated care for CJ-involved youth and adults, b) improve health and wellness, c) support improvements in social determinants of health including homelessness and CJ outcomes by reducing recidivism, and d) support improvements in the treatment engagement of juvenile justice youth and their families. Unique program features include transitional supports from correctional and/or inpatient hospital settings, leveraging the CCBHC's mobile outreach capacity, peer supports, telehealth, and care managers.