As witnesses to workplace sexism, male leaders have the opportunity to leverage both their relative social privilege as men and authority as leaders to enact allyship. However, allyship is fraught. Expression of indignation may be viewed by observers as unprofessional, yet a muted response may lead observers to question their motives for allyship. Further, allyship that does not hit the mark may have a ripple effect on observers’ perceptions of the leader-ally, victim, transgressor, and organization. Thus, the present research (1) examined whether emotion expression during allyship influences observers’ motive inferences of the leader-ally, (2) examined whether emotion expression influences favorability of the leader-ally, and (3) explored how a leader-ally’s emotional (or not) allyship behavior influences observers’ perceptions of the victim, transgressor, and organization. Study 1 (n = 298) showed that prejudice confrontation accompanied by anger or sadness (vs. not) is associated with intrinsic motive inferences of the leader-ally, and anger is seen as more appropriate and sincere when confronting prejudice. Study 2 (n = 112) showed that the leader-ally was viewed as more favorable when prejudice confrontation was accompanied by anger (vs. not) because the leader-ally was perceived as more sincere. Finally, qualitative data from thought-listings across both studies showed that leader-allies’ anger expression was associated with greater calls for accountability of the transgressor and more positive impressions of the organization. However, anger expression also wrought highly polarized responses toward the victim, consisting of both support and victim-blaming. Thus, authentic but measured emotion expression during confrontation is recommended.