The purpose of this study is to examine the effects of service quality in the Senior Employment Program on perceived post-participation changes and to empirically identify differences in influencing factors across program types. Using data from the 2022 Senior Employment and Social Activity Support Survey, a multiple regression analysis based on the Social Service Quality Measurement (SSQM) model was conducted on 3,078 participants. Through the analysis, the effects of the four dimensions of service quality (outcome, environment, interaction, and social quality) on perceived changes were measured. The results are as follows: First, higher service quality significantly improved perceived changes (economic, social, psychological, and developmental) across all program types, with the exception of Senior-friendly Enterprises. Second, the key influencing factors varied distinctly by program type. In Social Service and Senior Internship types, which primarily involve baby boomers, outcome quality (compensation) emerged as the most decisive factor in enhancing perceived changes. In contrast, in the Public Activity type mainly involving the older-old population, environmental and interaction quality were identified as critical determinants of positive change. These findings emphasize that senior employment policies must move beyond mere quantitative expansion and focus on tailored qualitative improvements that align with the specific characteristics and needs of each program type. In particular, this study provides significant policy and practical implications by demonstrating that enhancing service quality serves as a substantial mechanism for realizing Active Aging among the elderly in a super-aged society.