School counselors in South Korea are prone to emotional exhaustion due to job demands. To develop effective interventions for managing this exhaustion, it is essential to examine the relationship between emotion regulation strategies (ER), such as suppression and reappraisal, and exhaustion. Using a daily diary method and the Random Intercept Cross‐Lagged Panel Model (RI‐CLPM), this study explored how daily fluctuations in ER and exhaustion interact over 5 workdays with 111 school counselors. Results showed that emotional exhaustion persisted over time with a carry‐over effect, while emotion regulation did not carry over across days. Suppression and exhaustion mutually influenced each other over time, with higher suppression levels linked to greater exhaustion the following day in a specific context. Reappraisal showed context‐dependent effects, sometimes alleviating but occasionally exacerbating exhaustion. These findings emphasize the need for context‐sensitive interventions.