Ms. Fornés, who was called Irene by friends, leaves no immediate survivors. Her romantic partners over the years included the writer Susan Sontag and the writer and artists’ model Harriet Sohmers Zwerling.
María Irene Fornés was born in Havana on May 14, 1930. Her family was poor, and she had little formal education, though her parents were book lovers and her mother, Carmen, taught school. Her father, Carlos, a low-level Civil Service worker, died shortly before she moved with her mother and a sister to New York City in 1945.
Ms. Fornés held a variety of jobs, including one in a factory that made medals for the military. Taking up painting, she studied for a time with the Abstract Expressionist Hans Hofmann, whose “push-pull” theory of painting — that the juxtaposition of abstract forms and their surrounding space creates a sense of depth and movement — influenced her work as a playwright and director.
“I compose my plays guided not by story line but more by energies that take place within each scene, and the energies that take place within one scene and the scene that follows,” she said in 1990. “It’s like Hofmann’s push-pull in that the narrative doesn’t control how the play proceeds, but the development of the energies within the play.”
In the 1950s Ms. Fornés lived in Europe, mostly in Paris, where she was inspired, she said, by the original production of Samuel Beckett’s “Waiting for Godot.”
She taught playwriting at New York University, the Padua Hills Playwrights Festival in California, the Intar Hispanic American Arts Center in Manhattan and elsewhere. The playwrights Paula Vogel, Sarah Ruhl, Nilo Cruz and Eduardo Machado, among others, credit her as an influence.
“I taught with her at N.Y.U.,” Mr. Kushner said, “and every grad student I worked with told me she had changed their lives.”