This article introduces civic purpose as a construct for learning about civic development in adolescence. Civic purpose, defined as a sustained intention to contribute to the world beyond the self through civic or political action, integrates the components of motivation, civic activity, and future-oriented civic intention. We present results from a mixed methods longitudinal study that used the civic purpose framework, in which 1,578 high school seniors took a survey, 50 participated in an interview, and nine additional adolescent "civic exemplars" participated in both the survey and the interview. Two years later, 480 participants took the survey again and 34 participated in a second interview. A small percentage of the study's subjects exhibited full civic purpose across three different types of civic activity (political, community service, expressive), while a larger percentage demonstrated precursory forms of civic purpose, with evidence of some but not all components of civic purpose. Key contributors to the development of civic purpose were: identity salience; beliefs and values; and invitation from one or more adults.