Cognitive, communicative, and linguistic forces have been theorized to inhere in all metaphor use in real world contexts, with Steen (2011) describing these forces as constitutive and interacting ‘dimensions’ of metaphor. This paper proposes that cognition, communication, and language should be seen not just as crucial dimensions of individual metaphoric utterances, but also of their circumstances and contexts of use. In other words, purposive real world discourse activities impose various demands of a cognitive, communicative, and linguistic nature on speakers, and these shape the characteristics of metaphors used in definitive ways. This paper characterizes the discourse activity of psychotherapy along the three dimensions, and shows how the strategic use and management of metaphors in psychotherapy is, and ought to be, determined by interacting cognitive, communicative, and linguistic considerations. From this, it is suggested that the effectiveness of therapeutic metaphors can be evaluated in terms of their “discourse career” (Steen, 2011, p. 54) over a series of therapy sessions. The paper concludes by highlighting the value of psychotherapy to metaphor study, and of metaphor study to psychotherapeutic practice.