What happens when performance defies social and political boundaries? Performing Transgression offers a new cultural history of non-elite spectacle in Heian Japan (794–1185), uncovering how performances on the margins—boisterous dengaku music and dance, daring sangaku acrobatics, and the infectious lyrics of imayō songs—challenged and fascinated the aristocracy. Ashton Lazarus reveals how these unruly arts were documented by the very elites they unsettled, appearing in historical chronicles, diaries, prose, poetry, and illustrated scrolls. More than mere precursors to later forms like noh and kyōgen, these performances formed a dynamic cultural force with real political impact. By tracing their influence through literary studies, performance studies, and historiography, Lazarus rethinks the interplay between politics, class, and culture in Heian Japan. Performing Transgression illuminates how acts of defiance and creative expression resonate across time, offering fresh insights into the ways performance bridges the vanished past and the present.