Psychologists have broadly conceptualized moral identity as the degree to which one prioritizes and defines oneself in terms of moral goals, values, and commitments. We offer a new moral identity measure: one that integrates philosophical ethical theory with an Eriksonian identity perspective specific to adolescence and emerging adulthood. Participants (N = 215) completed our new measure along with four other measures of moral behaviors and motivations. Participants formed unique clusters based on (a) choosing Thomistic virtues versus choosing non-virtues, and (b) the degree to which they reflected upon and committed to their chosen virtues/non-virtues. We found expected group differences among the clusters in integrity and civic engagement motivation, providing evidence of validity. Our new measure offers a promising approach to moral education for adolescents and emerging adults.