Through a qualitative approach this study documents life experiences that youth with a history of sustained social and political participation judge as significant in the development of their civic commitment. Data is drawn from in-depth interviews to 6 Chilean youth (3 ages 16-19; 3 ages 20-24 years) of diverse socioeconomic condition, with a history of 3-7 years of active participation in prosocial and political organizations. Grounded theory was used to generate inductive knowledge of the processes that led to commitment and further sustained civic participation. Participants' trajectories of commitment illustrate both individual and contextual sources that motivate their sustained action. Participants identify with social and political causes and integrate them to their personal identities. Their sustained social action is related to identification with the goals of the organizations they belong to. Their accounts convey a collective sense of we developed through working toward shared goals with other organization members. Findings speak to the role that youth can play in advancing social and political ideologies and are discussed in light of identity theory and sociopolitical development. (Contains 1 figure.)