Born in Greenwood, South Carolina, Cornwell moved to Pennsylvania at age sixteen, living first in Yeadon with her aunt, then in Philadelphia with her mother, who moved north when Cornwell was eighteen. She graduated from Temple University in 1948. She worked as a journalist for local newspapers and a clerical worker for government agencies.
Cornwell has had work published in Feminist Review, Labyrinth, National Leader, Los Angeles Free Press and The Negro Digest, were among the first to identify the author as a black lesbian.
Cornwell was honored by the Annual Lambda Literary Festival which was held in Philadelphia in 2000.
- Black Lesbian in White America (Naiad Press, 1983)