There have been few research studies to examine the positive mental health of Asian adolescents. The aim here is to examine the factorial structure, internal consistency, test-retest reliability, and convergent/discriminant validity of a Korean version of the Mental Health Continuum–short form (K-MHC-SF), a newly developed self-report scale for positive mental health assessment, in a sample of South Korean adolescents. The Korean sample comprised 547 high school students (57% were female), ranging in age from 14 to 17 years (mean age = 16.08 years, SD = 0.34). Confirmatory factor analysis revealed that the K-MHC-SF replicated the three-factor structure of emotional, psychological, and social well-being found in earlier studies. Another confirmatory factor analysis supported the correlated two-factor model of mental health and mental disorder. The internal consistency of the overall K-MHC-SF was .91. The total score on the K-MHC-SF significantly correlated with a measure of life satisfaction ( = .58) and a measure of self-esteem ( = .57). In addition, the attempt at categorical classification revealed that 11.7% were in the category of positive mental health, characterized as flourishing, and 13.0% were in the category of absence of positive mental health, described as languishing. The results of the present study suggest that the K-MHC-SF is a psychometrically sound instrument for measuring the three lower-order dimensions of subjective well-being.