Margaret Mitchell was born in Atlanta, Georgia to Eugene Mitchell, a lawyer, and Mary Isabelle Stephens, a suffragist of Irish Catholic origin. Mitchell's brother, Stephens, was four years her senior. She often used the nickname "Peggy. Her childhood was spent in the laps of Civil War veterans and of her maternal relatives, who had lived through the Civil War

After graduating from Washington Seminary (now The Westminster Schools), she attended Smith College, but withdrew following her final exams in 1918. She returned to Atlanta to take over the household after her mother's death earlier that year from the great Spanish flu pandemic of 1918 (Mitchell later used this pivotal scene from her own life to dramatize Scarlett's discovery of her mother's death from typhoid when Scarlett returns to Tara Plantation).

Shortly afterward, she defied the conventions of her class and times by taking a job at the Atlanta Journal, where she wrote a weekly column for the newspaper's Sunday edition as one of the first woman columnists at the South's largest newspaper. Mitchell's first professional writing assignment was an interview with an Atlanta socialite, whose couture-buying trip to Italy was interrupted by the Fascist takeover.
Mitchell married Red Upshaw in 1922, but they were divorced after it was revealed that he was a bootlegger. She later married Upshaw's friend, John Marsh, on July 4, 1925; Marsh had been best man at her first wedding and legend has it that both men courted Mitchell in 1921 and 1922, but Upshaw proposed first.

Occupation
From 1922 to 1926, Mitchell wrote dozens of articles, interviews, sketches, and book reviews, including interviews with silent-screen star Rudolph Valentino, high-society murderer Harry K. Thaw, and a Georgia prisoner who made artificial flowers from scraps and sold them from his cell to support his family
She also wrote profiles of prominent Georgia Civil War generals. The first of these were so popular in Atlanta, that her editors assigned her several more. Scholars believe that it is her research for the profiles that later led her to write Gone With the Wind.

Using Mitchell's scrapbooks from the Hargrett Rare Book and Manuscript Library at the University of Georgia, editor Patrick Allen collected 64 of the columns Mitchell considered her best work. They were published in 2000 under the title Margaret Mitchell, Reporter.

Her portraits and personality sketches in particular show a promise of her skill to portray the kind of characters who made Gone With the Wind the second best-selling novel in history.[3] Even as a supposedly neutral reporter, her irrepressible personality shines through. This collection of Mitchell's journalism transcends fact-gathering, and shows Mitchell as a young woman and a compelling snapshot of life in the Jazz Age South.

Writing Gone with the Wind
Mitchell is reported to have begun writing Gone With the Wind while bedridden with a broken ankle. Her husband, John Marsh, brought home historical books from the public library to amuse her while she recuperated. After she supposedly read all the historical books in the library, he told her, "Peggy, if you want another book, why don't you write your own?" She drew upon her encyclopedic knowledge of the Civil War and dramatic moments from her own life, and typed her epic novel on an old Remington typewriter. She originally called the heroine "Pansy O'Hara", and Tara was "Fontenoy Hall". She considered naming the novel Tote The Weary Load or Tomorrow Is Another Day.

Mitchell wrote for her own amusement, and with solid support from her husband, kept her novel secret from her friends. She hid the voluminous pages under towels, disguising them as a divan, hid them in her closets, and under her bed. She wrote the last chapter first, and skipped around from chapter to chapter. Her husband regularly proofread the growing manuscript to help in continuity. By 1929, her ankle had healed, most of the book was written, and she lost interest in pursuing her literary efforts.

While Mitchell used to say that her Gone With the Wind characters were not based on real people, modern researchers have found similarities to some of the people in her life, and people she knew or heard of. For example, the character Rhett Butler may have been modeled after her first husband. The last thing he said to her (supposedly) was, "My dear, I don't give a damn", which is what Rhett says to Scarlett before he leaves her in the book, Frankly was added for the movie.