The National Security Cutter (NSC) is the U.S. Coast Guard’s (USCG) largest acquisition program to date. Despite the NSC’s significance, its acquisition (2002–present) has suffered numerous performance and cost-related setbacks ostensibly linked to Human System Integration (HSI) issues. In this thesis, we provide a historical HSI case study of the NSC program focusing on manpower, highlighting critical gaps in early concept analyses. While current USCG policy provides definitive guidance on HSI’s inclusion in acquisition programs, little evidence exists linking HSI-related decisions to specific system performance and life-cycle cost outcomes. We use process tracing to systematically establish linkages between USCG HSI policy, NSC program decisions, and specific system performance and life-cycle cost outcomes, illustrating the importance of HSI’s inclusion early in the acquisition life cycle. We produce a template for analyzing HSI decisions and outcomes in large-scale acquisition programs and provide a model for future systems engineering case studies. Our research will guide future program managers and HSI researchers in program management planning endeavors. Finally, our recommendations include the reinforcement of early and iterative HSI tradeoff considerations, organization and program-level integration of HSI in major program integrated product teams, strict adherence to USCG policy-defined HSI-related activities, and purposeful HSI case study taxonomy.Lieutenant Commander, United States Coast GuardApproved for public release. Distribution is unlimited