Understanding the factors that affect student engagement remains important in service-learning. The purpose of this study was to examine the relationships between purpose in life, civic mindedness, class engagement in service-learning, and personal need for structure. Especially, this study investigated the moderating effect of personal need for structure on the relationship between purpose in life and class engagement, as well as the relationship between civic mindedness and class engagement. A cross-sectional non-experimental design was adopted in this study. A total of 171 students were recruited from a service-learning course designed in the 2018 and 2019 spring semesters at a large research university in the USA. SPSS statistical software and Hayes' PROCESS were utilized to analyze the data. Study results showed that purpose in life is positively associated with civic mindedness ([beta] = 0.41, p < 0.01) and class engagement ([beta] = 0.21, p < 0.01). Also, civic mindedness is positively related to class engagement ([beta] = 0.25, p < 0.01). Personal need for structure moderates the relationship between civic mindedness and class engagement ([beta] = -0.38, p < 0.01). Theoretical and practical implications and limitations were also provided in this study.