The death of Beaux's American mother soon after her birth and her subsequent abandonment by her French father caused the child to be raised in the protective Philadelphia home of her maternal grandmother and aunts. Beaux began her training as an artist under her aunt, Eliza Leavitt, and continued under Kathrine Drinker, a history painter. Around 1872, she studied briefly with the Dutch artists, Adolf Van der Whelen, and soon she was teaching drawing herself at Miss Sandford's School. Throughout the 1870s, she made money by drawing fossils for the U.S. Geological Survey, and by painting children's portraits on porcelain.
Beaux was possibly a student at the Pennsylvania Academy of the Fine Arts where her name appears on the register from 1877 to 1879, but she later denied this, citing her uncle's opposition to her studying there. Between 1881 and 1883 she did had bi-monthly classes with William Sartain, whose textural, fluid brushwork was undoubtedly a great influence.
A year after her successful exhibition of Les Derniers Jours de'Enfance (private collection) at the 1887 Paris Salon, Beaux left for France with her cousin May and enrolled at the Academie Julian. There she received favorable critiques from William Adolphe Bouguereau and, especially, Tony Robert-Fleury. After a summer spent with artists Alexander Harrison, Charles Lesar, and Arthur Hoeber at Concarneau, Brittany, and a six-week trip to Italy, she returned to Paris to study at the Academie Colarossi as well as in Jean-Joseph Benjamin Constant's private studio. Spring of 1889 was spent painting portraits in England and visiting with the daughter-in-law of Charles Darwin, Maud DuPuy Darwin. Beaux continued her portrait work in Philadelphia from her returned in August 1889, until shifting her primary residence to New York several years later.
Introduced into New York cultural society through her friendship with the Richard Watson Gilder family, she soon made a reputation for herself, exhibiting for the first time at the National Academy in 1892 and winning the Dodge Prize the following year. In the annual exhibition of 1914 the Academy awarded her its Saltus Medal, and in the winter exhibition of 1915, the Proctor prize. In 1895 she was asked to teach a portraiture class at the Pennsylvania Academy of the Fine Arts, a position she kept for twenty years.
The hanging of six of her portraits at the 1896 Champs de Mars exhibition, Paris, signaled international recognition of her energetic, brightly colored, mature style. The next ten years are generally seen as her most fruitful and experimental. With John Singer Sargent and William Merritt Chase, Beaux was a leading practitioner of the "international style" of portraiture. The market for her work became quite brisk, and in 1905 her success enabled her to design and build a summer home, Green Alley, in Gloucester, Massachusetts.
Her later career was punctuated by such important commissions as three paintings of European war heroes for the U.S. War Portraits Commission (1919-20) and a self-portrait for the Uffizi Gallery, Florence (1925). However, her painting activity was sharply curtailed when in 1924 she suffered a debilitating broken hip; this problem was compounded by arthritis and failing vision. She nevertheless embarked on a new project, spending three years writing her autobiography, Background with Figures, which was published in 1930. In 1934 she saw her work celebrated in a major retrospective exhibition organized by the American Academy of Arts and Letters.
