The evidence suggests that Vera Charles of Auntie Mame is not based on Helen Hayes—for one thing, Hayes is explicitly name-checked when Gloria says she’d loved Vera in Mary of Scotland. For another, it’s unlikely that Helen Hayes, staunch Republican, would have been at all friendly with Mame Dennis. But she’s referred to as “the First Lady of the American Theatre,” which was an epithet given to Hayes. Her best friend was Lillian Gish, First Lady of American Cinema; she would have been beneficiary of Hayes’s estate, had she not predeceased Hayes by less than a month.
Both women, in fact, had careers stretching back to the early cinema. In fact, Gish’s stage career was earlier, and Hayes was onscreen first. She did two shorts in 1910, probably both lost, with “Jean the Vitagraph Dog.” She was also in “The Dancing Town,” the screen debut of Humphrey Bogart. In 1931, she had the lead in The Sin of Madelon Claudet, playing the lead; she won Best Actress for it. (In that same year, she was in Arrowsmith, playing a character who dies in a stupid way and is the only character in the book I care even a little for.) She dabbled in film for the next few decades, winning Best Supporting Actress for Airport—the longest gap between successive wins in Oscar history—and doing some television.
A lot of her TV appearances, in fact, were in ’50s-era TV playhouses, reprising roles she was known for on the stage. Including, of course, Mary of Scotland. She doesn’t seem to have originated a lot of well-known roles, but she was in vast numbers of revivals. She was Mrs. Antrobus from The Skin of Our Teeth. Amanda Wingfield of The Glass Menagerie a couple of times. Lyuboff Ranevskaya of The Cherry Orchard. She was even Pollyanna Whittier in 1917. One of her final stage roles was as Veta Louise Simmons in a revival of Harvey in 1970 starring James Stewart.
She also did, if you count an uncredited cameo as a tourist in Third Man on the Mountain, four movies for Disney. She’s delightful as Mrs. Steinmetz in Herbie Rides Again, and I have not yet seen One of Our Dinosaurs Is Missing, so I have no opinion on that one. But for me, she will always be the kind, compassionate Lady Gwendolyn St. Edmund, mistress of Candleshoe. A woman everything thinks is a pushover but who turns out to have a spine of steel. She is fierce when she has to be, and if she acts as though she’s found her lost granddaughter regardless of what said granddaughter says, well, maybe she has. In fact, Wikipedia does not list it as her final film role, as she narrated a film about a Polish nun who became a saint. But as far as acting for film, it was her last role. She did some television after that, though, including a couple of stints as Miss Marple.
She also endowed the Helen Hayes Hospital, a physical rehabilitation hospital in New York. I have no evidence of this, but I suspect it ties in at least some to the fact that she had a daughter who died of polio. The hospital had originally been pretty much exclusively for people suffering its after effects, and that seems likely to me as how she got involved with the hospital. It wouldn’t surprise me, further, if it ends up with some long-COVID patients in the days to come. Helen Hayes fought for the disabled and actually got things done.