Depressive symptoms can be influenced by different factors, including job types. In this study, we identified factors that affect depressive symptoms among South Korean workers by job type using data from the Korea National Health and Nutrition Examination Survey. Examined respondents were between 40 and 69 years (N = 9375). A complex sample linear regression analysis revealed various significant factors based on job type. For office workers, the number of household members, health-related quality of life, diabetes, sitting time, subjective health, and stress were significant influencing factors for depressive symptoms (explanatory power of 23.2%) (p < 0.001). For service workers, gender, health-related quality of life, food intake, aerobic exercise, sitting time, subjective health, and stress were significant influencing factors for depressive symptoms (explanatory power of 49.6%) (p < 0.001). For labor workers, gender, type of living, health-related quality of life, BMI, weight change, weight control, aerobic exercise, diabetes, subjective health, and stress were significant influencing factors for depressive symptoms (explanatory power of 35.8%) (p < 0.001). These differences highlight the need for customized programs targeted at each job type to maintain and promote mental health among workers.