This study examines the mechanisms by which cognitive diversity affects team performance in India’s banking sector, an industry characterized by digital transformation and hierarchical organizational norms. Grounded in the social cognitive theory, we propose a triadic model in which team efficacy mediates the relationship between cognitive diversity and performance, while team learning moderates the efficacy–performance pathway. Data were collected from 39 banking teams (392 respondents: 33 team leaders and 359 team members) using a three-wave, time-lagged survey design. Psychometric analyses confirmed strong internal consistency (α = 0.869–0.905) and appropriate team-level aggregation (ICC (1) = 0.18–0.23; ICC (2) = 0.72–0.78). Covariance-based structural equation modelling revealed that cognitive diversity exhibited both a direct positive association with team performance (β = 0.113, p < .01) and an indirect association mediated through team efficacy, with bootstrapped confidence intervals (0.071–0.152) confirming robustness. Team learning significantly strengthened the efficacy–performance relationship, with conditional indirect effects increasing from 0.034–0.104 under low-learning conditions to 0.099–0.208 under high learning conditions. These findings advance the social cognitive theory by establishing team efficacy as the psychological mechanism linking diverse cognitive inputs to coordinated action and team learning as a critical boundary condition in high-power-distance contexts. Practically, this study demonstrates that banking organizations must systematically cultivate collective efficacy and embed continuous learning routines to harness the performance benefits of cognitive diversity.