To explore who goes to aggressive and antisocial extremes on behalf of their group we primed perceptions of (a) group prototypicality (peripheral vs. central) and (b) ease of acceptance by the group. Participants were members of self‐significant groups—fraternities and sororities (N = 218). Drawing on social identity theory, uncertainty‐identity theory and the social identity theory of influence through leadership, we found, as predicted, that peripheral members who believed it was easy to be accepted were most likely to intend to engage in and support antisocial and aggressive intergroup behaviors. This effect was somewhat stronger among males than females, and strengthened among the most highly identified participants. The research's potential for understanding socially harmful intergroup violence is noted.