In more recent years, Day had been an animal rights advocate. Her Doris Day Animal Foundation confirmed her death at her Carmel Valley, California, home. The foundation said she was surrounded by close friends.
"Day had been in excellent physical health for her age, until recently contracting a serious case of pneumonia, resulting in her death," the foundation said in an emailed statement.
With her lilting contralto, wholesome blonde beauty and glowing smile, she was a top box office draw and recording artist known for such films as "Pillow Talk" and "That Touch of Mink" and for such songs as "Whatever Will Be, Will Be (Que Sera, Sera)" from the Alfred Hitchcock film "The Man Who Knew Too Much."
Over time, she became more than a name above the title. Right down to her cheerful, alliterative stage name, she stood for the era's ideal of innocence and G-rated love, a parallel world to her contemporary Marilyn Monroe. The running joke, attributed to both Groucho Marx and actor-composer Oscar Levant, was that they had known Day "before she was a virgin."
For those of us in my generation, Doris Day was synonymous with Hollywood icon. She would no doubt remind us, upon this day of her passing, “Que sera sera,” but we will miss her dearly anyway. Rest now in our hearts forever, Ms. Day.— George Takei (@GeorgeTakei) May 13, 2019
Day herself was no Doris Day, by choice and by hard luck. Her 1976 tell-all book, "Doris Day: Her Own Story," chronicled her money troubles and three failed marriages.
"I have the unfortunate reputation of being Miss Goody Two-Shoes, America's Virgin, and all that, so I'm afraid it's going to shock some people for me to say this, but I staunchly believe no two people should get married until they have lived together," she wrote.
A.E. Hotchner, who collaborated with Day on her memoir, said she had a "sweet and sour" existence and never let her personal difficulties "change her attitude toward people."
"She was such a positive, absolutely enchanting woman," he told The Associated Press on Monday. "And she was so loved."
Day received a Presidential Medal of Freedom in 2004. Although mostly retired from show business since the 1980s, she still had enough of a following that a 2011 collection of previously unreleased songs, "My Heart," hit the top 10 in the United Kingdom. The same year, she received a lifetime achievement honor from the Los Angeles Film Critics Association.
Celebrities and notable figures who have recently passed away
The Humane Society of the United States, of which The Doris Day Animal League is an affiliate, praised Day as a pioneer in animal protection.
In 1987, Day "founded one of the first national animal protection organizations dedicated to legislative remedies for the worst animal abuse," said the league's executive director, Sara Amundson. Her foresight "led to dozens of bills, final rules and policies on the federal level," which helped end abusive videos, protect chimpanzees from invasive research and regulate the online sale of puppies.
"She is an icon in the animal protection world and will be sorely missed for her singular advocacy," Amundson said.
Paul McCartney, a friend, called Day "a true star in more ways than one."
"Visiting her in her Californian home was like going to an animal sanctuary where her many dogs were taken care of in splendid style," he said in a statement. "She had a heart of gold and was a very funny lady who I shared many laughs with."
He cited films like "Calamity Jane," ''Move Over, Darling" and others and said he would "always remember her twinkling smile and infectious laugh."
Day "was kind and decent, onscreen and off; she maintained her friendship with Rock Hudson after his AIDS diagnosis, in a climate of fear and abandonment - one of his last appearances was on a TV show with her," playwright Paul Rudnick tweeted.
Born to a music teacher and a housewife in Cincinnati, Day dreamed of a dance career but at age 12 broke her leg badly when a car in which she was traveling was hit by a train. Listening to the radio while recuperating, she began singing along with Ella Fitzgerald, "trying to catch the subtle ways she shaded her voice, the casual yet clean way she sang the words."
Day began singing at a Cincinnati radio station, then a nightclub, then in New York. A bandleader changed her name to Day after the song "Day after Day" to fit it on a marquee.
A marriage at 17 to trombonist Al Jorden ended when, she said, he beat her when she was eight months' pregnant. She gave birth to her son, Terry, in early 1942. Her second marriage also was short-lived. She returned to Les Brown's band after the first marriage broke up.
Her Hollywood career began after she sang at a Hollywood party in 1947. After early stardom as a band singer and a stint at Warner Bros., Day won the best notices of her career with 1955's "Love Me or Leave Me," the story of songstress Ruth Etting and her gangster husband-manager. She followed with "The Man Who Knew Too Much," starring with James Stewart as an innocent couple ensnared in an international assassination plot. She sang "Que Sera, Sera" just as the story reached its climax.
But she found her greatest success in slick, stylish sex comedies, beginning with 1959's Oscar-nominated "Pillow Talk," in which she and Hudson played two New Yorkers who shared a telephone party line. It was the first of three films with Hudson.
In "That Touch of Mink," she turned back advances from Grant and in "The Thrill of It All" played a housewife who gains fame as a TV pitchwoman to the chagrin of obstetrician husband James Garner.
The nation's theater owners voted her the top moneymaking star in 1960, 1962, 1963 and 1964.
Her first singing hit was the 1945 smash "Sentimental Journey," when she was barely in her 20s. Among the other songs she made famous were "Everybody Loves a Lover," ''Secret Love," and "It's Magic," a song from her first film, "Romance on the High Seas."
Critic Gary Giddins called her "the coolest and sexiest female singer of slow-ballads in movie history."
Day was cast in "Romance on the High Seas" after Judy Garland and Betty Hutton bowed out. Warner Bros. cashed in on its new star with a series of musicals, including "My Dream Is Yours," ''Tea for Two" and "Lullaby of Broadway." Her dramas included "Young Man with a Horn" and "Storm Warning."
Her last film was "With Six You Get Eggroll," a 1968 comedy about a widow and a widower who blend families.
In the 1960s, Day discovered that failed investments by her third husband, Martin Melcher, left her deeply in debt. She eventually won a multimillion-dollar judgment against their lawyer.
With movies trending toward more explicit sex, she turned to television to recoup her finances. "The Doris Day Show" was a moderate success in its 1968-1973 run on CBS.
Day had married Melcher in 1951. He became her manager, and her son took his name. In most of the films following "Pillow Talk," Melcher was listed as co-producer. He died in 1969.
In her autobiography, Day recalled her son telling her the $20 million she had earned had vanished and she owed around $450,000, mostly for taxes. Terry Melcher, who died in 2004, became a songwriter and record producer, working with such stars as the Beach Boys. He was also famous for an aspiring musician he turned down, Charles Manson. When Manson and his followers embarked on their murderous rampage in 1969, they headed for a house once owned by Melcher and instead came upon actress Sharon Tate and some visitors, all of whom were killed.
Day married a fourth time at age 52, to businessman Barry Comden in 1976.
Her wholesome image was referenced in the song "I'm Sandra Dee" in the 1971 musical "Grease," which included the lyrics: "Watch it, hey, I'm Doris Day/ I was not brought up that way/ Won't come across/ Even Rock Hudson lost/ His heart to Doris Day."
Day's foundation released a statement following the announcement of her passing:
Since the '70s, Day had focused her energies on the Doris Day Animal Foundation. Her lifelong compassion for animals compelled her to fight animal testing and to advocate for spay/neuter education and outreach programs in the U.S. Today, her early Spay Day program had become an international event, with World Spay Day providing thousands of free or reduced-cost spay and neuter surgeries in 75 countries. The Doris Day Animal Foundation continues to provide support to smaller rescue organizations nationwide, with a special focus on those assisting senior pets.
Doris' passionate work on behalf of dogs, cats, horses, sea lions, raptors and other animals in need of rescue, veterinary care and adoption will not end. The Doris Day Animal Foundation is committed to continuing its work as a grant-giving organization, funding smaller animal welfare non-profits across the country. Doris' wishes were that she have no funeral or memorial service and no grave marker. Friends and fans wishing to remember Doris Day, are encouraged to visit dorisdayanimalfoundation.org.
The Associated Press contributed to this story.