Jones died Thursday of natural causes at her home in Malibu, according to Leslie C. Denk, a spokeswoman for the Norton Simon Museum in Pasadena.
But she was best known for her movie career. In all, she starred in more than two dozen films, playing opposite such A-list actors as William Holden, Joseph Cotten and Gregory Peck.
In addition to her best-actress win for "Bernadette," Jones was nominated for an Academy Award for leading roles in three other films: "Love Letters" (1945), a melodrama in which an amnesiac is cured through the love of a man, played by Cotten; the western epic "Duel in the Sun" (1946), with Peck; and "Love Is a Many-Splendored Thing" (1955), in which she played Dr. Han Suyin opposite Holden. She was also nominated as best supporting actress for "Since You Went Away" (1944), in which she starred with her first husband, Robert Walker.
The tall, sensitive Jones might never have risen to stardom but for Selznick, who was the first to see something special in the beautiful "big-eyed girl" named Phylis Isley who showed up in his New York office to test -- although not very well -- for the part of Claudia in the 1943 film of the same name. (Dorothy McGuire won the role.) After seeing her second test, he decided she was "the best sure-fire female star to come along since Leigh and Bergman" --referring to Vivien Leigh and Ingrid Bergman, both then under contract to the producer.
He found the young actress a new name and began grooming her for stardom, finding Jones her first big role in "Bernadette" and, afterward, producing or choosing most of her films. He endlessly pestered Hollywood with his memos about her makeup, her camera angles, her costumes. She was his protege, his obsession, his crusade, eventually his lover and, finally, his wife.
His adoration of her, said film critic David Thomson, shaped the rest of his life and fueled "one of the great gossip-column melodramas of the time."
"She was an ardent young actress before she met Selznick," Thomson wrote in "The New Biographical Dictionary of Film." "But it is hard now to be sure whether we would know her if his great wind had not picked her up like a leaf."
Jones was born in Tulsa, Okla., on March 2, 1919, the daughter of the owners and stars of Isley Stock Co., a tent show that toured the Midwest. She became interested in acting during her school years and eventually studied at Northwestern University and the American Academy of Dramatic Arts in New York.
It was at the academy that she met Walker, whom she married in 1939 and with whom she had two sons, Robert Walker Jr. and Michael Walker.
After several failed attempts to break into Hollywood, the two actors settled in New York City, and Jones finally got her chance for a screen test with Selznick.
By that time, Selznick was almost 40 and had already produced the epic "Gone With the Wind" and a string of popular and important films, including "David Copperfield," "A Tale of Two Cities" and "Rebecca." He was looking for another "GWTW" -- and another star to discover.
"The Song of Bernadette," a 20th Century Fox film directed by Henry King, was the vehicle Selznick picked to introduce Jones to the American public.
It was, everyone agreed, perfect casting. Jones, who was Catholic and had gone to a convent school, had the kind of wide-eyed innocence that made her believable as Bernadette Soubirous, the French peasant girl who saw a vision of the Virgin Mary in a grotto.
"I cried all the way through 'Bernadette' because Jennifer was so moving and because I realized then I had lost the award," said Ingrid Bergman, who was nominated for an Oscar for her role in "For Whom the Bell Tolls" the same year Jones won.
At the time, Jones was a wife and mother, but even that tame image was not what the studio wanted for the actress it had playing a virginal mystic. For months, Jones was asked to hide her family life and present herself as a real-life Bernadette.
That changed after Selznick arranged for Jones and Walker to play opposite each other in Jones' second starring film, the World War II tear-jerker "Since You Went Away" from 1944. To promote that film, publicity stories were churned out about "Mr. and Mrs. Cinderella" and their contented home life with their children.
By then, however, the relationship was frayed, and the couple divorced in 1945. Walker, who had starred in "See Here, Private Hargrove," "Strangers on a Train" and opposite Judy Garland in "The Clock," died in 1951.