基于个人-领导匹配视角，通过3个时点对213名领导与一线服务员工的配对调研，采用多项式回归和响应面分析，探讨领导乐观与下属乐观之间匹配程度（领导-下属乐观匹配）如何通过认知信任和情感承诺影响员工主动服务行为，以及领导-下属年龄匹配在上述过程中的调节作用。研究结果表明：领导-下属乐观匹配促进一线服务员工的主动服务行为；在匹配情况下，与“低-低”匹配相比，员工主动服务行为在领导-下属乐观的“高-高”匹配时更多；认知信任和情感承诺在领导-下属乐观匹配与主动服务行为间起部分中介作用。此外，领导-下属乐观匹配对主动服务行为的间接影响存在年龄差异。相较非领导年长情形，当领导年长时，员工认知信任的中介作用更强；相较领导-下属年龄不一致情形，当年龄一致时，员工情感承诺的中介作用更强。

Based on the perspective of person-supervisor fit, this study examines how leader-follower optimism fit affects proactive customer service performance among frontline service employees through cognition-based trust and affective commitment, as well as the moderating role of leader-follower age fit in this relationship. By analyzing three-wave matched survey data from 213 dyads of leaders and followers, the results of polynomial regression and response surface analysis show that leader-follower optimism fit promotes proactive customer service performance among frontline service employees. In case of optimism fit, proactive customer service performance is higher when the leader and follower are both highly optimistic than when they are both low in optimism. Cognition-based trust and affective commitment play a mediating role between leader-follower optimism fit and proactive customer service performance. Besides, age fit moderates these relationships. Compared with cases in which the leader is younger than or the same age as the follower, when the leader is older, the mediating role of cognition-based trust is stronger; compared with cases involving a large age gap between the leader and the follower, the mediating role of affective commitment is stronger.