<p>Followers do not passively observe leaders—they actively infer intentions, and these inferences shape their attitudinal and behavioral responses toward leader behaviors. While such attributional processes are central to social psychology, they have been largely overlooked in leadership research. Instead, leadership measurement models often conflate inferred intentions with behavioral constructs, making causal claims indeterminate. Empirical evidence, in its current form, risks misleading leadership theory into assuming causality without clarifying whether leadership outcomes result from leaders’ actions or from what followers believe they want to achieve through those actions. This conceptual entanglement introduces a unique form of endogeneity bias by embedding into behavioral measures what would otherwise be treated as an omitted explanatory variable—namely inferred intentions. This conflation is particularly salient in responsible leadership research and, when combined with challenges such as limited dimensional coverage, weak qualitative grounding, and overreliance on reflective models, poses substantial challenges to valid and reliable measurement. To address these concerns, this study develops and validates the Responsible Leadership Intentions (RLIs) Index, a new instrument designed to capture how followers evaluate a leader’s underlying intention. A multi-methods approach was adopted, combining a literature review, topic modeling of qualitative interviews, and a cross-sectional survey of service sector employees (N = 506). The RLIs index was modeled as a second-order reflective–formative construct across five distinct but complementary dimensions. The scale demonstrated strong psychometric properties and predictive power in explaining overall leader trust. This study contributes to reducing endogeneity bias in leadership research and marks a conceptual shift toward intention-based evaluations of leadership.</p>