The study explored the roles of commitment, emotional stress, and interpersonal relationships in sustaining individuals' engagement in collective action. Two collective action cases, differing in duration, issue, and territorial rootedness, were analyzed. The processes underlying sustained engagement were probed in 32 semistructured interviews conducted with antiglobalization activists (N = 13) and opponents to a high-speed railroad (N = 19). Our findings showed that collective action can be stressful, but that there are proximal and distal factors that can counterbalance the disruption and sustain engagement. The proximal factors are embedded in the circumstances of involvement, and these factors concern interpersonal relationships, organizational mechanisms, and the psychological interface between the individuals and the concrete collective action environment. The distal factors are related partly to the individual and partly to the broader community from which the individual absorbs general values and norms. Copyright © 2011 John Wiley & Sons, Ltd.