This study aimed to design and propose a comprehensive model for applying blockchain technology to enhance financial sustainability within the automotive parts manufacturing supply chain. This applied, developmental research used a mixed-methods approach. In the qualitative phase, semi-structured interviews were conducted with ten senior managers and experts from ten major automotive parts manufacturing companies, and data were analyzed using grounded theory coding. In the quantitative phase, the identified variables were validated and refined through a fuzzy Delphi technique and pairwise comparison questionnaires distributed among 214 senior, financial, IT, and supply chain managers from 150 companies. Interpretive Structural Modeling (ISM) and MICMAC analysis were employed to determine hierarchical relationships and driving–dependence power among components. The fuzzy Delphi analysis identified ten key components for implementing blockchain in financially sustainable supply chains, including “Legal and Regulatory Framework,” “Standardization,” “Technology and Infrastructure Management,” “Policy Making,” “Blockchain Information Management,” “Centralized Business Model,” “Supply Chain Integration,” “Financial Flexibility,” “Financial System Development,” and “Achieving Sustainable Goals.” ISM revealed a seven-level hierarchical structure, with “Legal and Regulatory Framework” and “Standardization” as foundational independent drivers, while “Financial System Development” and “Achieving Sustainable Goals” were dependent outcomes at the top. Strengthening the legal and regulatory foundation and establishing industry-wide standards are prerequisites for successful blockchain adoption in financially sustainable supply chains. Organizational policies and technology management should subsequently evolve to improve transparency, trust, and risk reduction, ultimately enabling sustainable financial systems and environmental goals in the automotive parts industry.