Using archival data from 972 military officers who participated in a 5-week team-based leadership development program, the authors tested 5 hypotheses concerning the implications of age-and gender-based role incongruence for individuals' mastery of 2 knowledge categories and their observed leadership potential (OLP). As hypothesized, greater age was related to less mastery of both teamwork knowledge and strategy knowledge, whereas female gender was related to less mastery of strategy knowledge only. Another focus was on possible evaluative bias in OLP, with individuals' knowledge mastery and career-relevant circumstantial factors taken into account. Notably, knowledge mastery partially explained the appreciable overall relationship of age with OLP, yet fully explained the modest overall relationship of gender with OLP. Therefore, some evaluative bias existed for age but not gender. The overall pattern of results revealed that an intrapersonal consequence (i.e., knowledge mastery) of demographic-based role incongruence overshadowed any interpersonal bias in evaluation, pointing to a new direction for theory and research.To facilitate the emergence of capable leaders, many organizations are implementing formal systems for evaluating leadership potential among