Day, who turned 97 on April 3, broke into show business as a singer, and recorded a hit, "Sentimental Journey," with bandleader Les Brown in 1945. That and “Que Sera, Sera” — which Day performed in Alfred Hitchcock's 1956 thriller "The Man Who Knew Too Much" — were her biggest chart-toppers.
The multitalented Day would jump off the turntable and on to the big screen, with credits in 39 movies. Her best-known screen works include "Calamity Jane" in 1953, "Love Me or Leave Me" in 1955, "The Man Who Knew Too Much" in 1956, "Pillow Talk" in 1959, "Lover Come Back" in 1960 and "Move Over, Darling" in 1963.
"During her three decades of work in film, Day starred in nearly every genre, not just as a singer/dancer but as an actress with superb comic timing, a natural talent for interpreting a role and a gift for evoking emotion," her foundation said.
Paul McCartney paid tribute by saying he had visited Day several times at her California home, "where her many dogs were taken care of in splendid style."
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The famed musician added, "I will miss her but will always remember her twinkling smile and infectious laugh as well as the many great songs and movies she gave us. God bless Doris."
Day was the first Hollywood star many of America's Baby Boom generation ever knew.
"For those of us in my generation, Doris Day was synonymous with Hollywood icon," actor George Takei said in a statement. "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."
Day was married four times, which conflicted with her squeaky-clean public and big-screen persona. In her 1976 book, "Doris Day: Her Own Story," the actress said her real life was much more complicated.
With three bad marriages in her rear-view mirror at the time, Day said couples should live together before walking down the aisle — a risque, forward-thinking stance at the time.
"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.
Doris Mary Ann von Kappelhoff was born April 3, 1922, in Cincinnati, the child of Alma Sophia Welz and Frederick Wilhelm Von Kappelhoff, who was a music teacher.
The youngest of three kids, Day was named after silent movie actress Doris Kenyon.
While Day never won an Oscar, she was honored with a Presidential Medal of Freedom in 2004.
President George W. Bush declared that it was "a good day for America when Doris Mary Ann von Kappelhoff ... decided to become an entertainer."
The humble Day didn't understand all the fuss when Bush announced she'd be honored.