Objective: This study examined the influences of general characteristics, temperament, social support, and emotional regulation on the positive psychological capital of adolescents. The data were collected from 672 middle school students living in Gwangju. Methods: Data were analyzed using Pearson correlation analyses and hierarchical regression analyses. Results: Temperament best explained positive psychological capital. In terms of individual factors, self-emotion regulation had the greatest effect on positive psychological capital, followed by friend support, persistence temperament, others emotion regulation, academic achievement, harm avoidance temperament, gender, and family support, in that order. Conclusion: The results for the effects of temperament, social support and emotion regulation on adolescent’s positive psychological capital highlights the important roles played by the temperament, social support, and emotion regulation in improving an adolescent’s positive psychological capital. The study contributes to the literature by proving fundamental insights into an adolescent’s psychological strengths and higher quality of life.