Ms. Kanin's career was formed in a more genteel time in American show business when husband-and-wife writing teams (Garson Kanin and Ruth Gordon, Frances Goodrich and Albert Hackett, Pheobe and Henry Ephron) were common. She met her spouse, artist Michael Kanin (Garson was his brother), on the lot at RKO, where both of them were then employed.
Together they wrote such films as "Sunday Punch" (1942), "My Pal Gus" (1952), "Rhapsody" (1954), "The Opposite Sex" (1956), "The Right Approach" (1961), in which they adapted a play by Garson Kanin, and "Swordsman of Siena" (1962). Their most noted success was the 1958 Doris Day-Clark Gable romantic comedy "Teacher's Pet," which netted them their sole Oscar nomination.
Alone, Fay Kanin wrote the 1948 comedy Goodbye, My Fancy, set in a dormitory at a woman's college. Directed by Sam Wanamaker and produced by her husband, it was a hit, and won actress Shirley Booth a Tony Award. The play was made into a movie in 1951 starring Joan Crawford.
With Michael, she wrote the 1954 Broadway comedy His and Hers, which starred Celeste Holm, and Rashomon, which was based on the Japanese stories by Ryunosuke Akutagawa, and starred Claire Bloom and Rod Steiger. It was made into a television movie twice, in 1960 and '61.
For a time in the 1950s, the Kanins were blacklisted by the House Committee on Un-American Activities. They were unable to find work until director Charles Vidor insisted on using them for the Elizabeth Taylor film "Rhapsody."
She won considerable attention when she shifted from film to television in the 1970s, winning Emmy nominations for a series of serious, socially conscious TV movies, including "Tell Me Where It Hurts" (1974), about a wife and mother who is looking for something more from life; "Hustling" (1975), a widely seen movie about a reporter investigating the world of prostitution; "Friendly Fire" (1979), about a couple trying to find out the truth about the death of their son in the Vietnam War; and "Heartsounds" (1985), about an ailing doctor who is confronted with the broken medical system of which he is a part. She won the award for the first. All of these were solo projects, as Michael Kanin had by then backed away from writing.
Ms. Kanin didn't return to Broadway until 1985, when she wrote the book for the ill-fated Harold Prince musical Grind. Set in a bi-racial burlesque house in 1933, it was a famous flop. It lasted only a few weeks, but got the writer her only Tony nomination.
Ms. Kanin, who called herself a feminist, was president of the Academy of Motion Arts and Sciences from 1979 to 1983. She was only the second woman to hold the post.
Fay Mitchell was born in New York on May 9, 1917. She graduated from the University of Southern California at the age of 19 and immediately embarked on a screenwriting career. She was soon hired by RKO Pictures as a script reader.
Michael Kanin died in 1993.
She is survived by her son Josh. A second son, Joel, died when he was 13.