Billed as Jay Presson, she began her career as an actress with a featured role in "An Angel Comes to Brooklyn" (1948), but soon turned to writing. Her first novel, "Spring Riot" was published in 1948 and she spent much of the 50s scripting episodes of TV shows like "Philco Playhouse" and "Playhouse 90". After her 1955 marriage to producer Lewis M Allen, she began being billed as Jay Presson Allen. Alfred Hitchcock tapped her to adapt the 1964 thriller "Marnie". Her stock rose with her adaptation of her own 1966 play "The Prime of Miss Jean Brodie" (1969), which provided a tour de force vehicle for Maggie Smith, who won the Best Actress Oscar. Allen reteamed with Smith for "Travels With My Aunt" (1972), which earned another Best Actress nod for the actress. That same year, the screenwriter triumphed with "Cabaret", adapted from the stage musical. Brilliantly directed by Bob Fosse, "Cabaret" was acclaimed as one of the few successful stage-to-screen transfers. The musical numbers were mostly confined to the stages of the Kit Kat Club and the surrounding drama set in 30s Nazi-era Germany was compelling. Nominated for ten Academy Awards, including Best Picture and Best Screenplay, it won eight, including Best Director, Best Actress (Liza Minnelli) and Best Supporting Actor (Joel Grey). Allen went on to script another musical vehicle for a star: the sequel "Funny Lady" (1975) for Barbra Streisand. While not as successful as 1968's "Funny Girl", it nevertheless had its moments, particular in the witty repartee between Brice and husband Billy Rose (James Caan), although critics carped that the script was a by-the-numbers romance. After executive producing the modest feminist tale "It's My Turn" (1980), Allen teamed with Sidney Lumet for the screen version of her novel "Just Tell Me What You Want" (1980). A romantic comedy, the film featured fine performances by Alan King and Ali MacGraw and is recalled as the final screen appearance of Myrna Loy. Although often plunging deeply into the emotional lives of her characters, Allen was at her darkest with Lumet's "Prince of the City" (1981), which centered on police corruption.
Allen's best known small screen work is perhaps "Family", but she also created the short-lived 1988 ABC series "Hothouse", about life at a medical center in a serene country setting. An adaptation of her one-person play "Tru", which starred Robert Morse as Truman Capote, aired in 1992 as part of PBS' "American Playhouse".
Allen appeared in the 1995 documentary "The Celluloid Closet" discussing the images of homosexuals in films as several of her scripts featured overt or closeted gays. "The Prime of Miss Jean Brodie" had lesbian undertones. "Cabaret" was ripe with gay characters, including Michael York's bisexual lead. Roddy McDowall played gay in "Funny Lady". "Family" was one of the first TV series to tackle to topic of homosexuality: in one episode, the son discovers his best friend is gay, while in another, the daughter discovers her favorite teacher is a lesbian and even questions her own sexuality.