Rolefulness is a psychological concept that refers to a person's continuous sense of role satisfaction in their daily lives. This study introduces the rolefulness development theory--that social rolefulness emerges from social experiences first and then facilitates internal rolefulness. Hence, using a sample of high school students, this study conceptualizes a four-quadrant model of rolefulness development and examines its validity. The model includes four types of rolefulness-- integrated, developing, immature, and groundless--and compares scores of self-esteem, identity, and depression among these groups. Results show that self-esteem and identity scores were highest in the integrated group and lowest in the immature group, depression scores were highest in the immature group and lowest in the integrated group, and the groundless group also had high depressive tendency. These results support the validity of the quadrant model and clarified the relations between rolefulness development and adolescents' mental health.