PurposeDifferential leadership does not necessarily bring only negative effects, as it may also become an incentive management strategy. This study explores whether outsiders can actively become insiders through proactive personality traits, or whether they can actively approach resource controllers to remove obstacles at work and enhance their performance in a Chinese cultural setting.MethodologyA stratified random sampling method was used. The sample objects were medical staff from hospitals in the six urban districts of Beijing. In 2021, a total of 900 online questionnaires were distributed. 524 valid questionnaires were recovered.Main findingsThe results show that differential leadership, defined as favoritism towards insiders and prejudice against outsiders, can cause changes in employees’ sense of organizational justice and in-role performance. Meanwhile, by introducing ‘proactive personality’ as an independent variable that also acts as a moderator, our study confirms that, under differential leadership, employees with a proactive personality can actively improve situational barriers and have better work performance.Implications/applicationsOur research offers managers the following advice: First, it is better to look not only at relationships, but also to understand an employee’s personality characteristics, whether it has a superficial or deep role at work, in order to reduce the turnover rate and to raise productivity. Second, it is important to teach employees to serve customers with a sincere appreciation of their point of view, rather than focusing on presenting an outward appearance of friendliness.Novelty/originalityThis paper contributes to the theory of proactive personality, emotional labor, and differential leadership. Contrary to previous studies, our research has used ‘proactive personality’ as both a distractor and a predictor at the same time. Also, insiders favored by leaders are not found to perform better at work.