Based on the relief theory and similarity attraction theory, this study investigates the influence of leader humor on employee creativity through the mediate impact of employees’ perceived workload, occupational coping self-efficacy, and employee similarity perception with a leader as a potential moderator. The data were collected through an online survey that included matched questionnaire data from 351 employees and their direct leaders in China. This study used SPSS 26 software and Mplus 7.0 software to analyze the data and found that (1) leader humor has a significant positive impact on employees’ creativity; (2) employees’ perceived workload and occupational coping self-efficacy mediated the positive relationship between leader humor and employee creativity; (3) similarity perception negatively moderated the influence of leader humor on perceived workload, and it also positively moderated the influence of leader humor on occupational coping self-efficacy. In addition to corroborating and expanding on previous findings regarding the relationship between leader humor and employee creativity during the COVID-19 period, the aforementioned conclusions also derive management implications for fostering employee creativity and reducing employee workload from the perspective of leader humor.