Hearon was born in 1931 in Marion, Kentucky. She attended the University of Texas at Austin, graduating with a Bachelor of Arts in 1953. Armadillo in the Grass, her first novel, was begun in 1962 and accepted for publication by Knopf in 1967.

Hearon has been awarded fiction fellowships from the Ingram Merrill Foundation, the Guggenheim Foundation and the National Endowment for the Arts. She has also received the Texas Institute of Letters award twice, and a lifetime achievement award from the Texas Book Festival. Five of her short stories were awarded NEA/PEN syndication Short Story Prizes.

Her novel Owning Jolene won an American Academy of Arts and Letters Literature Award.