Аннотация:We theorize that engagement, conceptualized as the investment of an individual's complete self into a role, provides a more comprehensive explanation of relationships with performance than do well-known concepts that reflect narrower aspects of the individual's self. Results of a study of 245 firefighters and their supervisors supported our hypotheses that engagement mediates relationships between value congruence, perceived organizational support, and core self-evaluations, and two job performance dimensions: task performance and organizational citizenship behavior. Job involvement, job satisfaction, and intrinsic motivation were included as mediators but did not exceed engagement in explaining relationships among the antecedents and performance outcomes.