Allen nee Jay Presson was born in San Angelo, Texas, on March 3, 1922. She began her career in television in the fifties with the Philco Playhouse. In 1962 she adapted Muriel Spark's novella The Prime of Miss Jean Brodie into a successful Broadway and London play. She subsequently wrote the film adaptation. Also in the early 1960s, she wrote the screenplay for the Alfred Hitchcock movie Marnie. In 1968, Allen returned to Broadway, adapting a French play by Pierre Barillet and Jean-Pierre Gredy into the comedy Forty Carats. In the 1970s, the scribe wrote the screenplays for Cabaret receiving an Oscar nomination for her work, Travels with My Aunt, 40 Carats and Funny Lady. In 1982 she received an Oscar nomination for the screenplay for Deathtrap. That same year she adapted another Barillet and Gredy play, A Little Family Business, for Broadway. In 1989 she again found theatrical success with the one-man show Tru, which she wrote and directed. Tru ran for 297 performances at the Booth Theatre and earned star Robert Morse a Tony Award for Best Actor in a Play for his portrayal of Truman Capote. In 1991 Allen wrote and directed the less successful solo show The Big Love with Tracey Ullman.
Allen was married to prolific Broadway producer Lewis Allen, who produced Tru and The Big Love. He died in 2003. She is survived by a daughter and two grandchildren.