From a systemic functional perspective (SFL), the present study sets out to reflect upon a consecutive interpretation which the first author conducted at the inauguration of a Sino-US joint college in the US. With an attempt to explore the applicability of an SFL approach to the analysis of real interpreting texts, the study constructs a framework to capture and account for the (in)congruencies of the target text with the speaker’s source text. The framework is in turn tested to justify the choices the interpreter made, firstly against the background of his speaker’s “extemporaneous” variations from the potential three metafunctions of the speech, secondly in terms of the multi-role of the interpreter as the writer of the prepared speech, coordinator of the event, as well as subordinate of the speaker. The analysis shows that the interpreter held a holistic view of the interpreting context throughout the process, and that he pulled through the three critical moments by converting the speaker’s impromptu remarks to the designated line of meta-functional coherence.