Career adaptability is a prerequisite for ensuring college students' career development and effectively solving career-related problems. Given that secure attachment positively contributes to adaptive functioning, this study examined the mediating effect of South Korean college students' maladaptive perfectionism on the relation between adult attachment insecurity and career adaptability. Further, gender differences in the mediational pathways from attachment insecurity to career adaptability were investigated. Participants include 212 college students (male = 49.1%, female = 50.9%) aged between 19 and 31 years (M[subscript age] = 22.50, SD = 2.15) living in South Korea. Results indicated that for male and female students, the relation between attachment insecurity and career adaptability is mediated by maladaptive perfectionism. The multigroup analysis revealed that the relations between attachment insecurity, maladaptive perfectionism, and career adaptability differed by gender. These results emphasize the importance of understanding college students' personality profiles and supporting their career adaptability based on their personality traits.