Our aim was to investigate the relationship between suppressing emotion and engaging with complaining customers at work and experience of depression and anxiety symptoms. We used nationally representative data from the Korean Working Condition Survey with 15,669 paid customer service workers. Job characteristics of "Engaging with Complaints", "Suppressing Emotion", experience of depression and anxiety symptoms were measured by self-reported questionnaires. Gender specific odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using multivariate logistic regression after controlling for age, income, education level, job satisfaction, and working hours per week. The results showed that people who were ‘Always Engaging with Complaints' (OR: 3.81, 95% CI: 1.83–7.96 for male, OR: 3.98, 95% CI: 2.07–7.66 for female) and ‘Always Suppressing Emotion' (OR: 2.33, 95% CI: 1.33–4.08 for male, OR: 2.83, 95% CI: 1.67–4.77 for female) were more likely to experience depression and anxiety symptoms compared to those ‘Rarely Engaging with Complaints' and ‘Rarely Suppressing Emotion', respectively. Additionally, there was an interactive relationship between those job characteristics. Our nationwide study demonstrates that mental health problems are incrementally related to how much service workers must engage with complaining customers and suppressing emotion at work.