In recent times, STEM graduates are confronting a decline in employment rates influenced by economic, social, cultural, and policy-related factors. Career decisions are closely linked to education, college experiences, and university settings. To comprehend the reasons behind the decline in STEM employment, it is essential to explore the relationships among these factors. This study aims to comprehensively examine differences in career motivation and career exploration behavior among 2,393 STEM undergraduates in Korea. Additionally, factors affecting career motivation and career exploration behavior were investigated. The findings indicate significant differences in perceived career motivation and career exploration behavior based on individual backgrounds and university characteristics. And analyzing the data, 37.8% of career motivation is explained by contextual supports, career barriers, individual backgrounds (grade, GPA), university characteristics (major fields, location), field to enter after graduation, and timing of job preparation. For career exploration behavior, 30.1% is explained by contextual supports, career barriers, individual backgrounds (gender, grade, GPA), university characteristics (major field, location), field to enter after graduation, and timing of job preparation. Practical implications underscore the need for tailored educational and policy support, considering individual backgrounds and university characteristics, to effectively address challenges faced by STEM graduates in the evolving employment landscape.