Fornés, who went by the name "Irene",[1] received nine Obie Theatre Awards[2] in various categories[a] and was a finalist for the Pulitzer Prize in Drama for 1990.

New Yorker critic Hilton Als wrote in 2010 that she had done "more than her fair share in terms of changing the face of theatre".

At the age of 19, she became interested in painting and began her formal education in abstract art, studying with Hans Hofmann in New York City and Provincetown, Massachusetts.

[11][12][13] Fornés's first step toward playwriting involved translating letters she brought with her from Cuba that were written to her great-grandfather from a cousin in Spain.

[14] In 1959, about the time she was working on La Viuda, Fornés entered into a romantic relationship with the writer Susan Sontag.

Fornés later described how, in the spring of 1961, her career as a playwright was launched when she tried to help Sontag, who was frustrated by her inability to make progress on a novel she was writing.

An absurdist two-character play, it was later renamed Tango Palace and produced in 1964 at New York City's Actors Studio.

Clive Barnes called it "a joy from start to finish" and praised the show's "dexterity, wit and compassion".

"[19] She came close to having her work performed on Broadway in April 1966, when Jerome Robbins directed The Office starring Elaine May.

[20] In Fefu and Her Friends (1977), Fornés begins and ends with the audience seated as a single group facing a traditional stage.

The play is considered to be feminist by critics and scholars, in that it offers a woman's perspective on female characters and their thoughts, feelings, and relationships.

Mud, first produced in 1983 at the Padua Hills Playwright's Festival in California,[25] explores the impoverished lives of Mae, Lloyd and Henry, who become involved in a love triangle.

[22][23] In Fornés' exploration of the world of Hispanic women in the US, the title character of Sarita begins in 1939 as a 13-year-old unwed mother in the South Bronx and at the end of the play enters a psychiatric hospital at the age of 21.

Some dialogue is in Spanish as Sarita contends with the two men in her life, the exploitative Julio and her rescuer the Anglo Mark.

[2] In August 2018, as Fornes' death neared, a 12-hour marathon performance of excerpts from her works was staged at New York's Public Theater.

Pulitzer Prize-winning writers Tony Kushner, Paula Vogel, Lanford Wilson, Sam Shepard, and Edward Albee credit Fornés as an inspiration and influence.

Paula Vogel contends: "In the work of every American playwright at the end of the 20th century, there are only two stages: before she has read Maria Irene Fornes and after."

"[31] As Fornés' reputation grew in avant-garde circles, she became friendly with Norman Mailer and Joseph Papp and reconnected with Harriet Sohmers.

[33] Philip Glass composed a 30-minute chamber opera for three singers accompanied by keyboard and harp based on Fornés' play Drowning.