The article explores the use of the Social and Emotional Health Survey-Secondary version (SEHS-S) with a sample of 975 Japanese students in Grades 7-9 attending schools located northwest of Tokyo. A confirmatory factor analysis using half the sample confirmed the four-factor structure of the SEHS-S, and further analyses verified its second-order factor model including Belief-in-Self, Belief-in-Others, Emotional Competence, and Engaged Living, all of which contribute to a latent second-order construct labeled Covitality. Additional SEM validity analyses found that the four identified first-order SEHS constructs and the second-order covitality construct were positively associated with subjective well-being. SEHS-S scores also predicted several variables indicative of positive school engagement for Japanese students, including academic performance, social relationships, and willingness to assist others. Results of the study are discussed in terms of the advantages of using strength-based assessments such as the SEHS-S for Japanese students and in promoting well-being in this population.