Kersti’s work unfolds at the intersections of the history of science, networks of power, and LGBTQ+ studies in medieval and early modern literature. Her current book project, Arcane Desires: Medieval Literary Magic and Transgressive Fictions, uses the premodern framework of sins contra naturam and transhistorical theories of fictionality to argue that contemporary authors used literary magic to engage in queer and trans imaginings of bodies, relationships, and sexual acts.

Their second project, Fetishizing the Past: Historophilia and Premodern Sexuality, interrogates medieval and early modern narratives of sexual desire that depend upon the pleasurable tension between past and present, engaging in what Kersti terms historophilia: an eroticism generated by the self-conscious interplay of dissonant temporalities.

Kersti has also worked extensively on premodern histories of science, focusing on the role of alchemy in the Latin Christian West and the Dar al-Islam, medieval notions of sexual morphology, and the role of natural philosophy in medieval romance. They have also published research on medievalism in video games, sadomasochism in Middle English literature, and digital humanities approaches to the study of medieval manuscripts.