<p>Organizations invest heavily in knowledge management, yet employees vary in tacit and explicit knowledge-sharing. Because prior research often treats knowledge-sharing as a uniform behavior, limited evidence explains how fairness-related and safety-related information jointly shape distinct contribution forms. Drawing on social exchange theory and risk-based perspectives, this study examined how organizational justice and psychological safety relate to both knowledge types and whether cooperative orientation conditions these relationships. We surveyed 397 knowledge-active office workers in Korea from organizations with more than 50 employees and formal KM policies and analyzed the data using structural equation modeling and conditional process tests. Distributive, procedural, and informational justice related positively to psychological safety and to both knowledge-sharing outcomes, and psychological safety partially mediated the organizational justice associations with tacit knowledge-sharing and explicit knowledge-sharing. Cooperative orientation moderated the organizational justice and psychological safety associations with explicit knowledge-sharing but not with tacit knowledge-sharing, and conditional relationships remained positive while marginal slopes attenuated at higher cooperative orientation. The findings clarify a knowledge-type-specific architecture that connects organizational justice to exchange expectations and to a disclosure pathway through psychological safety, while identifying cooperative orientation as a selective boundary condition for system-mediated contribution. For practice, justice-centered governance of KM routines and safety-oriented interaction norms jointly strengthen knowledge disclosure, and managers can calibrate reinforcement for explicit contributions to employees’ cooperative orientation.</p>