Prior research has identified benefits from certain emotion tactics in negotiation, particularly expressing anger to achieve short‐term gains. We demonstrate that such tactics can be strategically problematic due to their impact on an actor's emotions and felt trust. Through five studies, we find that negotiators' use of anger tactics during a negotiation increased their feelings of guilt and reduced the extent to which they felt trusted by their counterpart following the negotiation. We found this guilt to be the result of their aggressive tone and how they treated their counterpart. The guilt and diminished felt trust in turn motivated negotiators to engage in greater cooperative behaviors during the deal implementation process that benefited their counterpart, even if doing so was costly to the negotiator. Our results demonstrate that negotiator guilt and felt trust resulting from anger tactics influence the dynamic relationship between negotiators and their counterparts. This in turn has strategic implications for negotiators, who attempt to mitigate these negative feelings during the crucial implementation phase of a negotiated agreement.