Although in the country, a legal aspect of mandatory Corporate Social Responsibility (CSR) compliance is legally ensured in all the public sector banks (PSBs) in India, it is still debatable whether or not it has empirically transitioned in the form of concrete returns of financial security and sustainability. To fill this gap, this paper employs a two-pronged triangulation design involving a five-year prospective financial panel matrix (2021-2025) and a role-sensitive structural survey modelling of 384 validated stakeholders. Structural Equation Modelling (SEM) was performed through a stepwise set-up to isolate the role of internal employee awareness and external customer perceptions as signalling conduits between institutional CSR activities and perceived performance outcomes. Instead of exaggerating to cause arguments using solely cross-sectional data, the findings indicate that bank-level CSR is a crucial company cue that enhances internal capacity alignment and external behavioural confidence. The structural model also emphasises the role of internal stakeholder synchronisation, which is aligned with the Stakeholder Theory proposed by Freeman, as a key catalyst in the operation and leads to increased perceived institutional soundness, compliance accountability, and relational capital. These results indicate that sustainability interventions can be maximally rewarded when integrated into the operational and cultural systems of banking governance, offering a fine, role-specific view on stakeholder involvement in new banking markets.