Mary Louise Booth was born on April 19, 1831 in Long Island, New York, to William Chatfield Booth and Nancy Monswell Booth. Although she did attend public schools, she was primarily self taught and considered quite precocious. As soon as she could walk, her mother said she was following her about book in hand, begging to be taught to read stories for herself. Reportedly she read the Bible and Plutarch at five and Racine by the age of seven, and she had a particular aptitude for foreign languages. Her father was a miller and educator who believed that teaching was the only suitable career for a young lady and consequently, did not support her inclination toward becoming a writer. At eighteen, she rebelled after teaching in his school for only a few years and moved to Manhattan where she pursued a literary career.
She supported herself by sewing vests during the day while studying and writing in the evenings. Eventually she was hired by the New York Times where she wrote articles on education and women’s topics. During this time she became friends with Susan B. Anthony becoming acquainted through their mutual work in the New York State Teachers' Association to equalize educational opportunities. Mary became very active in the women’s rights movement, serving as secretary at the conventions in Saratoga, New York in 1855 and then again in New York City in 1860. While engaged in this work she also began her own historical writing. Her History of the City of New York was the first comprehensive history of the city to be published.
In 1856 she began her career as translator and translated more than forty works from French to English. During the Civil War she used her skills to promote the Union cause translating Count deGasparin’s The Uprising of a Great People: The United States in 1861. Reportedly she worked twenty hours a day and completed this task in less than a week..
In 1867 Harper Brothers began the weekly magazine Harper’s Bazaar and hired Mary as its editor. She held this position for twenty two years, earning what was then an impressive salary of $4,000 a year. During her tenure circulation reached 80,000. She never married although she was engaged briefly in 1887 during a trip to Venice.
She knew everyone who was anyone. President Lincoln, Georges Sand, Winslow Homer, Oliver Wendell Holmes. As the founding editor of Harper's Bazar, she performed a great service to suffrage, according to her friend Elizabeth Cady Stanton, by 'showing that a woman can...hold for years a place at the head of a profession so difficult and so arduous.’