PurposeThe main purpose of our study is to investigate the impact of daily leader humor behaviors on healthcare workers’ daily psychological state and behavioral outcomes.Design/methodology/approachBased on the conservation of resources (COR) theory, this study proposes that daily leader humor behaviors are positively related to healthcare workers’ daily positive affect, which in turn affects their next-day helping behaviors towards patients. These predictions hinge on healthcare workers’ difficulty in maintaining display rules. We conducted a lagged experience sampling methodology (ESM) survey of 621 complete daily observations from 93 healthcare workers who work in direct contact with patients at a large public hospital in China across consecutive 10 working days.FindingsResults of multilevel path analysis demonstrate that daily leader humor behaviors are positively related to healthcare workers’ same-day positive affect, and this positive affect enhances their next-day helping behaviors towards patients. Furthermore, healthcare workers’ higher difficulty in maintaining display rules attenuates the benefits of daily leader humor behaviors.Originality/valueBuilding on the COR theory and adopting a diary research design, this study shows daily fluctuations in leader humor behaviors and proposes a mechanism through which daily leader humor behaviors indirectly affect healthcare workers’ next-day helping behaviors. Thus, our study disclosed possible means for healthcare organizations to improve service quality.