Background: Primary Agricultural Cooperative Credit Societies (PACCS) represent the foundational tier of India's rural credit delivery architecture. In Tamil Nadu, nearly 4,290 such societies serve more than 12 million farm households, yet persistent concerns about non-performing assets, governance deficits, and technological obsolescence have eroded their developmental effectiveness. 
Objectives: This systematic review synthesises empirical evidence published between 2017 and 2026 to examine the interplay of digital transformation, financial viability, governance reforms, and rural sustainability across PACCS in Tamil Nadu. 
Methods: Following PRISMA guidelines, 104 peer-reviewed studies, institutional reports, and policy documents were systematically selected from Scopus, Web of Science, EBSCO, ProQuest, Google Scholar, NABARD, RBI, and NITI Aayog repositories. Thematic synthesis and quality assessment using the Mixed Methods Appraisal Tool (MMAT) were employed. 
Results: Evidence reveals that digitally enabled PACCS reported a 34–41% reduction in operational costs and up to a 28% improvement in loan recovery rates. Districts with core banking solutions exhibited significantly lower NPA ratios (average 14.3%) compared to non-digitised counterparts (22.1%). Governance reforms aligned with the Model Bye-Laws (2024) correlated with improved member participation and credit disbursement growth. 
Conclusion: PACCS can remain viable rural financial intermediaries if digital transformation is pursued alongside robust governance reforms, diversified revenue strategies, and climate-sensitive credit products. Targeted policy support from NABARD, TNCAB, and state government remains indispensable.