The internal organisational mechanisms through which green service innovation (GSI) translates into SDG-aligned hotel sustainable performance remain insufficiently understood. Drawing on stakeholder theory and the natural-resource-based view, this study tests a moderated mediation model positioning environmental management accounting (EMA) and eco-innovation (ECI) as parallel mediators of the GSI–hotel sustainable performance (HSP) relationship, with stakeholder pressure as a moderating boundary condition. Hotel sustainable performance is conceptualised as a reflective higher-order construct encompassing environmental performance (SDG 13), economic performance (SDG 8, SDG 12), and social performance (SDG 11, SDG 3). Survey data were collected from 356 managers across 192 four- and five-star hotels in Istanbul and Antalya, Türkiye, and analysed using PLS-SEM in SmartPLS 4. GSI is positively associated with HSP, EMA, and ECI; both mediators are independently and positively associated with HSP; and bias-corrected bootstrapping confirms significant partial mediation via both pathways. Formal moderated mediation tests confirm that stakeholder pressure strengthens the GSI–EMA and GSI–ECI relationships and amplifies the full capability-mediated pathway to SDG-aligned performance, with significant indices of moderated mediation whose confidence intervals exclude zero. The model achieves substantial explanatory power (R² = 0.703), and PLSpredict confirms out-of-sample predictive relevance, with PLS-SEM RMSE below the linear model benchmark for all HSP indicators. The findings advance SDG-oriented sustainability theory and provide evidence-based guidance for hotel managers, industry associations, and policymakers on green capability investment for SDG-aligned competitive advantage.