Her death was announced by the Writers Guild of America, West.  In 1979 Ms. Kanin, who was a playwright as well as a screenwriter, became just the second female president of the Academy of Motion Picture Arts and Sciences, the advocacy organization that presents the Oscars. The first was Bette Davis, who resigned after two months in 1941.  Ms. Kanin was known for telling stories with a distinctly female perspective. Her play “Goodbye, My Fancy” was a comedy about a congresswoman and her misguided impulse to rekindle a college romance with a man who had since become the college president. It opened on Broadway in 1948, ran for more than a year and was later made into a movie with Joan Crawford.  “I’m a big feminist,” Ms. Kanin declared at the time. “I’ve put into my play my feeling that women should never back away from life.”  Ms. Kanin collaborated with her husband, Michael Kanin — the brother of Garson Kanin, who also wrote films with his wife, Ruth Gordon — on numerous screenplays, sometimes with other writers. They included “Sunday Punch” (1942), set in a boardinghouse for boxers, and “Rhapsody” (1954), about a young woman (Elizabeth Taylor) torn between two musicians.  For “Teacher’s Pet” (1958), a romantic comedy about a crabby and dismissive newspaper editor (Gable) and a spunky journalism teacher (Day), the Kanins were nominated for an Academy Award. They also wrote a stage play, “Rashomon,” adapted from Ryunosuke Akutagawa’s short stories and Akira Kurosawa’s film; the 1959 Broadway production starred Claire Bloom and Rod Steiger and was later adapted as a western film called “The Outrage,” with a cast including Ms. Bloom, Paul Newman and Edward G. Robinson.  But Ms. Kanin grew disenchanted with the film industry, feeling it had become less hospitable to the relationship dramas that intrigued her. As her husband withdrew from the writing partnership, she turned to television.  She won her first Emmy in 1974, for the movie “Tell Me Where It Hurts,” starring Ms. Stapleton as a housewife who realizes there is more to life than cooking and cleaning for a husband. A year later she was nominated for an Emmy and won a Writers Guild Award for the television movie “Hustling” (1975), a raw look at prostitution in Manhattan. It set a Saturday night ratings record for ABC, drawing some 50 million viewers.  “I was hooked on the chance to deal with a subject usually presented to the public in a romantic haze of myth,” Ms. Kanin said. She did six months of research, which included waiting with prostitutes in police station bullpens.  In 1979 Ms. Kanin wrote and co-produced the Emmy and Peabody Award-winning film “Friendly Fire.” Based on a book by C. D. B. Bryan that originally appeared as a series of articles in The New Yorker, it is about a conservative Iowa farm couple, Gene and Peg Mullen (played by Ned Beatty and Ms. Burnett) who become activists against the Vietnam War after their son is killed by fire from his own troops.  One reason she chose to do the movie, Ms. Kanin said, was the death of her own son, Joel, at 13 from leukemia in 1958. “I had all the angers Peg had, many of them misdirected,” she said. “I was angry at the doctors like Peg was angry at the Army.”  Thirty-four years ago Ms. Kanin was elected president of the Motion Picture Academy by a board that consisted of 34 men and one other woman. Although the gender ratio has changed since then — there are 19 women on the Academy’s current 57-member board of governors — Ms. Kanin was the last woman to serve as president. In her four one-year terms, the maximum allowed, she was widely credited with pushing the Academy to help preserve Hollywood films.  Fay Mitchell was born in New York on May 9, 1917, the only child of a clothing store manager and a retired vaudeville actress.  After she graduated from the University of Southern California at 19, Ms. Kanin, who already had screenwriting ambitions, was hired by RKO Pictures as a script reader.  It was there that she met Mr. Kanin, a writer who would go on to win an Oscar with Ring Lardner Jr. for their screenplay for “Woman of the Year” (1942), the first of the Spencer Tracy-Katharine Hepburn films. They married in 1940; he died in 1993. Ms. Kanin’s survivors include her son Josh; two granddaughters; two stepgrandsons; and a great-grandson.  In a speech in 2003 Ms. Kanin recalled her start as a playwright. Her brother-in-law Garson Kanin had brought the script of “Goodbye, My Fancy” to a major producer, Max Gordon, who said he loved it, but lamented that he could produce only one more play that season and had on his desk a comedy by George S. Kaufman and Edna Ferber, who had written the classic comedies “Dinner at 8” and “Stage Door.” “Now, if you were Max Gordon, which play would you do?” he asked Ms. Kanin, who reluctantly gave him the answer he wanted.  “I’ll be the producer,” Michael Kanin told his wife, and he then mortgaged their house to raise the money.  The Kaufman-Ferber comedy disappeared almost immediately, while “Goodbye, My Fancy” became a hit. The next time she met Mr. Gordon, Ms. Kanin said, he looked at her sadly.  “Why did you give me such lousy advice?” he asked.
Ms. Kanin wrote comedies and dramas about relationships for film, stage and television as well as movies about death in the Vietnam War and prostitution.