This article adds to the literature on smart girlhood by exploring the topic through Karen Barad's theory of post-human performativity. We focus on the transcripts of two participants from a larger study on girls and academic success in Canada in order to highlight the material, discursive, embodied, and temporal entanglements that co-produce the possibilities for girls' academic subjectivities. Using a diffractive methodology, we highlight the mutually arising agencies of bodies, hoodies, schools, grades, and media constructions of multi-talented 'supergirls.' This analysis highlights the importance of an intersectional approach to academic success alongside an understanding that inequalities, such as sexism, still endure for smart girls. We conclude by emphasizing the power of materiality in girls' everyday lives to shift understandings of self, school, and smartness, as well as the importance of moving beyond dichotomous and decontextualized accounts of girls' high achievement that have circulated for over twenty years.