The traditional view holds that professional interpreters should be transparent, invisible, passive, neutral, and detached, a view reiterated and reinforced in the prescribed interpreters' codes of conduct of national and international professional organizations. Such an idealized role construct, however, is from time to time deconstructed in real-life face-to-face interpreting events. In this paper, face-to-face interpreting is seen as a three-way communicative event in which the interpreter is a co-constructor of the interaction and can therefore be a powerful figure. From the perspective of interpreting as a socially-situated activity, the paper adopts Michel Foucault's concept of power, defining it not as the traditionally dominating force to monopolize, control, or rule, but as a kind of strategy, disposition, maneuver, tactic, or technique, functioning in a network of relations. Although interpreters often lack institutional power, they may be equipped with power within the exchange as a result of their bilingual and bicultural expertise. They may exercise this power by adopting various verbal and non-verbal strategies to negotiate, coordinate, check, and balance power relations. This can be specifically manifested in interpreters' social action as co-interlocutors, empowerment figures, or in the adoption of a non-neutral stance. Examples are cited from authentic interpreting events to analyze interpreters' power-at-work, focusing on their verbal and non-verbal behaviors, in particular, their positioning and gaze.