This present study aimed to investigate the association effect of obesity status, physical symptom, insecure attachment, and depression on psychological well-being in non-diabetic healthy Koreans. Height, weight, waist circumference, blood pressure, and socio-psychological questionnaires (insecure attachment, depression, and physical symptom psychological well-being, etc.) were examined in 123 healthy Koreans. Student t-test, correlation analysis, and mediation analysis were performed. Study subjects were divided into 2 groups based on body mass index (BMI, kg/m²): obesity (BMI ≥ 25, n = 36) and non-obesity (BMI < 25, n = 87). Obese people were older and showed higher proportion of males than non-obese ones. Regarding the values of socio-psychological test, obesity group showed lower insecure attachment, and higher physical symptom than non-obesity group. In correlation and mediation analyses, depression was positively related to insecure attachment and physical symptom in both BMI groups. Positive relationship between physical symptom and insecure attachment was observed only in non-obesity group, but not in obesity group. The effect of insecure attachment on psychological well-being was completely mediated by depression in both BMI groups. On the other hand, the effect of physical symptom on psychological well-being was completely mediated by depression in obesity group, but not in non-obesity group. In conclusion, this study presented that the effects of physical symptom and insecure attachment on psychological well-being were completely mediated by depression in obese healthy Koreans, but not in non-obese ones. It will provide useful data for extending the knowledge on the relationship between the physical health and mental health.