Her screen partnership with Rock Hudson was one of the biggest box-office draws of the 1950s and '60s.
In a statement at the time, she said: "I've always said that age is just a number and I have never paid much attention to birthdays, but it's great to finally know how old I really am".
The Doris Day Animal Foundation confirmed Day died early Monday at her Carmel Valley, Calif., home. She defined sunny, all-American wholesomeness.
Her 1976 tell-all book, "Doris Day: Her Own Story", chronicled her money troubles and three failed marriages, contrasting with the happy publicity of her Hollywood career. I like it. I like being happy.
Day became a star with back-to-back films in 1956 and 1957.
Day's lilting voice, wholesome blond beauty and ultra-bright smile brought her a string of hits, first on records, and later in Hollywood.
She was born Doris von Kappelhoff on April 3, 1922, in Cincinnati and headed to California at age 14 to be a dancer.
In 1960 and 1962 to 1964, Day was ranked No. 1 at the box office by American Exhibitors but her last feature film performance was in the 1968 romantic-comedy With Six You Get Eggroll, directed by Howard Morris, and co-starring Brian Keith, Barbara Hershey, George Carlin, and Pat Carroll.
Doris married four times and had a son, Terrence, with her first spouse Al Jorden, who was later adopted by her third husband, the late Martin Melcher, but he died in 2004.