Her death from respiratory polio at age 19 led to creation of the Mary MacArthur Memorial Fund, which provided money for research and for treatment of people with that disease.
[2] Hayes's pregnancy led to a "widely publicized theatrical controversy"[3] and an arbitration settlement after she suddenly left a Pacific Coast production of Coquette, causing the play to close.
The producer said that he should not have to pay the Actors' Equity Association's standard "two weeks' salary in lieu of notice" to the play's cast, because the pregnancy was covered by the contract's "act of God" clause.
[4] MacArthur attended Rosemary Hall girls' school in Greenwich, Connecticut,[2] and was a 1949 graduate of the American Academy of Dramatic Arts.
"[10] The trying aspect for MacArthur arose from "her mother's enviable reputation as the 'First Lady of the Theater'", while Hayes wanted "to see her own child captivate and hold an audience".
[10] The review noted that MacArthur "proved to be her mother's daughter, playing the part of Amy Grey with the teen-age perfection it calls for.
[15] MacArthur became ill in the summer of 1949 in Westport, Connecticut, while she was performing with Hayes in a pre-Broadway version of the comedy play Good Housekeeping.
The two-hour variety show, which Life magazine called the "biggest event of the theatrical year, junior division", raised $9,000 for the March of Dimes.