This article embeds the study of character development within the two-decades-long research program framed by the Lerner and Lerner model of positive youth development. Character development involves attaining the feelings, thoughts, and skills needed to act coherently across time and place to serve self and others in mutually beneficial, positive ways. Research in the U.S. and other nations suggests that there are three key features of successful character development initiatives for children and adolescents: Mentors and models, skill-building opportunities, and opportunities to participate in and to take a leadership role in valued family, school, and community activities. Implications of this research include the idea that character development can be the foundation on which other key facets of a person's thriving can be built (e.g., competence, confidence, connection, and caring), and can provide a key basis for enabling every young person to contribute positively to their own lives and to the enhancement of their families, schools, and communities.