Social enterprises must communicate mission without undermining commercial viability, yet empirical evidence on whether impact-oriented marketing supports financial sustainability remains limited, especially in emerging economies. This study examines the relationship between social impact marketing and financial sustainability among Indian social enterprises and tests whether stakeholder trust and perceived legitimacy mediate that relationship, while digital capability moderates it. Using survey data from 250 Indian social enterprises and hierarchical regression with bootstrapped mediation analysis, the study finds that social impact marketing is positively associated with financial sustainability (β = 0.502, p < .001). When the mediators are introduced, the direct association remains significant (β = 0.314, p < .001), while stakeholder trust (β = 0.205, p < .001) and perceived legitimacy (β = 0.140, p = .009) also show significant positive associations with financial sustainability. Bootstrapped indirect effects via stakeholder trust (β = 0.071, 95% CI [0.034, 0.115]) and perceived legitimacy (β = 0.048, 95% CI [0.012, 0.090]) are significant, indicating partial mediation. Digital capability has a positive main effect on financial sustainability (β = 0.156, p = .010), but its interaction with social impact marketing is not significant. Short open-ended responses reinforce the quantitative results by showing that the largest managerial bottlenecks concern impact evidence, mission–market translation, and constrained communication resources. The study contributes to social enterprise scholarship by positioning social impact marketing as a strategic capability linked to financial sustainability through relational and legitimacy mechanisms in the Indian context..