School counsellors in South Korea face significant emotional exhaustion due to their challenging occupational environment. Previous studies have shown that cognitive reappraisal (CR) reduces emotional exhaustion, whereas expressive suppression (ES) increases it. However, these findings predominantly rely on trait questionnaires within cross‐sectional approaches, overlooking the dynamic nature of emotion regulation (ER) strategy selection. Individuals may choose strategies that deviate from their general tendencies based on situational demands. There is limited empirical knowledge regarding the interaction between trait and state regulation strategies and their influence on exhaustion. Utilizing the strategy‐situation fit hypothesis, this study examines the context‐specific effects of ER strategies, considering both situational contexts and individual response tendencies. A multilevel analysis was performed to examine the influence of state and trait ER strategies on daily emotional exhaustion. A daily diary study was conducted for 5 days with 111 Korean school counsellors. Daily CR was associated with lower daily exhaustion and daily ES predicted higher daily exhaustion. Contrastingly, none of the trait ER strategies had an impact on daily exhaustion, but the trait level of both strategies significantly moderated the relationship between daily CR and exhaustion. The positive impact of daily CR was more pronounced in school counsellors who often utilized suppression strategies, and this impact was also evident in trait reappraisal. Re‐evaluating daily emotions instead of suppressing them may assist in coping with emotional exhaustion caused by work. The effectiveness of these strategies may vary based on an individual's inclination to regulate emotions as state and trait. ER may aid in implementing preventive interventions for school counsellors experiencing emotional exhaustion.