The present study aimed to investigate the effect of emotion regulation on the job engagement of novice school counselors while reflecting the variability and context of emotion regulation by utilizing a daily diary method. A sample of 100 South Korean school counselors completed the baseline and diary measures regarding emotion regulation and job demands and resources twice a day for 5 consecutive working days. Multilevel modeling was performed to analyze the nested data and test the research hypothesis. The use of state suppression negatively affected novice school counselors' job engagement. Cross-level interaction effects on momentary job engagement were found between state reappraisal and job resources, as well as between state suppression and job demands. The findings highlight how daily emotion regulation interacts with contexts at work to impact on momentary job engagement of novice school counselors, underscoring the importance of considering these dynamics when promoting engagement.