Despite the increasing interest in leaders’ health-promoting behavior, employees’ role in the effectiveness of such behavior and the mechanisms underlying how such leadership behavior affects their well-being have largely been ignored. We argue that health-promoting leadership behavior is most beneficial for employee well-being (here: exhaustion and work engagement) if it is congruent with employees’ expectations regarding their leaders’ health-promoting support. We further propose that congruent behavior relates to better employee- rated leader-member relationships (leader-member exchange, LMX) and to more health-promoting behaviors by employees, which, in turn, positively relates to their well-being. A field study and an experimental study largely supported our hypotheses. Polynomial regression analyses revealed that incongruence between expected and actual health-promoting leadership behavior negatively related to LMX quality. Furthermore, congruence effects varied with the level of health-promoting leadership: congruence at high levels (when both expected and actual health-promoting leadership behavior were high) was more strongly associated with LMX quality and employees’ self- care behavior than congruence at low levels. Our results highlight the pivotal role of employees’ expectations regarding leaders’ health support and help in building practical interventions with regard to leaders’ health promotion.