Acting the Part offers a paradigm for understanding how audiences participate in immersive theater, from physical spaces like the Globe in London to digital spaces like social virtual reality. Reading across twenty-first century productions of ancient Greek tragedies and William Shakespeare’s plays, E. B. Hunter proposes the concept of “enactivity” to describe the positionality audiences inhabit when their participation is critical to the narrative but cannot alter its intended course. This positionality is that of the archetype, the enactment of which is shaped by four production conditions: a historically resonant site, a canonical source, an immersive space, and a production-specific economy that incentivizes some behaviors and discourages others. At the heart of Acting the Part is a framework for identifying how a production’s management of these conditions gives rise to a range of archetypes, such as worshiper, sleuth, cinematographer, and others. Against the backdrop of an ever-increasing push for audience participation, Acting the Part sheds new light on the many ways in which productions shape that participation in real time.