The proportion of elderly individuals has been increasing in Korea. Under this condition, it is essential to understand the behavioral characteristics of elderly individuals to build adequate policies. The purpose of this research was to investigate the determinants of quality of life for Korean senior citizens, specifically, their subjective health and their regular medical, housing, and clothing expenditures. Data were collected from a Korean senior citizen research panel, and the study period was 2018–2020. Multiple linear panel regression analyses were conducted for the analysis of panel data, which includes ordinary least squares, random effects, and fixed effects. In the results, quality of life for older Korean adults was positively affected by subjective health and clothing expenditures. However, quality of life was negatively influenced by medical and housing spending. The results of this work could offer information for building policies for better senior welfare.