Cassils is a transgender artist who makes their own body the material and protagonist of their performances. Cassils' art contemplates the history(s) of LGBTQI+ violence, representation, struggle, survival, empowerment and systems of care. For Cassils, performance is a form of social sculpture: drawing from the idea that bodies are formed in relation to forces of power and social expectations, Cassils' work excavates historical contexts to examine the present moment.
 
Cassils has an upcoming solo exhibition at SITE Santa Fe and has had recent solo exhibitions at HOME Manchester; Station Museum of Contemporary Art, Houston; Perth Institute for Contemporary Art; Ronald Feldman Fine Arts, New York; Philadelphia Academy of Fine Arts; School of the Museum of Fine Arts, Boston; Bemis Center, Omaha; and MU Eindhoven.
  
They are the recipient of funding from the Ford Foundation (2023), the National Creation Fund (2022), a 2020 Paul D. Fleck Residency at Banff Center for Arts and Creativity, a Princeton Lewis Artist Fellowship finalist (2020), a Villa Bellagio Rockefeller Foundation Fellowship (2019), a United States Artist Fellowship (2018), a Guggenheim Fellowship and a COLA Grant (2017) and a Creative Capital Award (2015). They have received the inaugural ANTI Festival International Prize for Live Art, California Community Foundation Grant, MOTHA (Museum of Transgender Hirstory) award, and numerous Visual Artist Fellowships from the Canada Council of the Arts. Their work has been featured in New York Times, Boston Globe, Artforum, Hyperallergic, Wired, The Guardian, TDR, Performance Research, Art Journal and was the subject of the monograph Cassils published by MU Eindhoven and the catalog Solutions, published by the Station Museum of Contemporary Art, Houston (2020). Cassils' work was recently acquired by the Victoria Albert Museum, London; Art Gallery of Ontario, Toronto and the Leslie Lohman Museum, New York.

Cassils is an Associate Professor in Visual Studies at the University of Toronto.