Morning Star, revived in 1999 by Steppenwolf Theatre in Chicago, revolves around a widow and her extended family on New York's Lower East Side. Spanning 1910-1931, the play includes such historic events as the Triangle Shirtwaist fire, World War I and the Great Depression, shaping the lives and destinies of the family. Frank Galati directed the Steppenwolf production of the play, which was first seen at the Longacre Theatre in 1940. Ms. Ellstein was also an actress and press agent in her lifetime.

Ms. Ellstein's bigger success on Broadway was the 1953 play, The Fifth Season, a comedy about the dress business, which ran 654 performances. She was co-librettist of a 1950 musical called Great To Be Alive!, and penned the libretto for the 1962 opera, The Golem, by her husband-composer Abraham Ellstein, who died in 1963.

Ms. Ellstein — whose plays were under the name Sylvia Regan — had been a childhood friend of Group Theatre's Clifford Odets and wrote numerous plays including Every Day But Friday, A Hundred Million Nickels, Safe Harbor, 44 West, The Twelfth Hour and Zelda.

As an actress, Ms. Ellstein made her debut under the name Sylvia Hoffman (he birth name was Sylvia Hoffenberg) in a 1926 and later appeared in The Waltz of the Dogs and Poppa. She was promotions and public relations manager for the Theatre Union at the Civic Repertory Theatre (1932-26) and the Mercury Theatre Company (1936-38).

Before marrying Ellstein, her first marriage to James J. Regan ended in divorce.