Fitzgerald, a native of Dublin, died at home Sunday from Alzheimer's disease, the Hollywood Reporter said Monday.
Fitzgerald was only a teenager when she made her stage debut and went on to have a notable Broadway career, the Reporter said.
She made her U.S. stage debut in 1938 at the Mercury Theatre in "Heartbreak House" opposite Orson Welles. She actually launched a second Broadway career in 1971 with an acclaimed performance in the revival of "Long Day's Journey Into Night."
She is survived by a son and a daughter.