This study investigated the dietary behaviors and sustainable dietary life competencies of parents with children who use school food services according to dietary lifestyles, and included an analysis of data reported in the 2021 Korean Consumer Behavior Survey for Food. A total of 519 parents, the main purchasers of food in their households, were included in the study. Statistical analysis was conducted using the t-test, chi-test, factor analysis, and cluster analysis in SPSS (ver. 27.0). Four factors were extracted by factors analysis (interest in food quality and safety-seeking, convenience seeking, traditional dietary-trend seeking, and diverse taste seeking) to explain the dietary lifestyles of parents. Cluster analysis results indicated parents that explored dietary changes and those that maintained a traditional diet should be regarded as target segments. Parents who explored dietary changes were found to be significantly more likely to purchase HMR food and use delivery/take-out food sources than the traditional dietary group (P<0.01). In addition, the traditional dietary group had a significantly higher rate of having family breakfast and dinner than those that explored dietary changes (P<0.01). As regards sustainable dietary competency, those who explored dietary changes had a high score for the selection of agrifood (P<0.001). In contrast, the traditional dietary group showed a significantly higher preference for traditional foods (P<0.05) and considered family dining (P<0.01) and dining etiquette (P<0.05) to be more important. The results of this study suggest the need for education tailored according to parents' dietary lifestyles due to a shortage of sustainable dietary life competency.