Madeleine Sophie Barat was born to a Joigny barrel-cooper family — the youngest of four children. Her older brother Louis, a brilliant seminarian who had been ordained priest the day before the French Revolution suspended episcopal jurisdiction, took her under his strict tutelage at ten — moving her to Paris in 1795 and submitting her over five years to a punishing classical-theological curriculum (Latin, Greek, Scripture, ascetic theology) that her brother insisted on completing as a preparation for the religious life he had decided she should embrace.
She made vows in November 1800 at twenty as one of the four founding members of the Society of the Sacred Heart (Société du Sacré-Cœur, RSCJ in religious initials). The Society had been planned by Father Joseph Varin of the suppressed Jesuits as a women's parallel to the projected Jesuit restoration — specifically dedicated to the Catholic education of girls of the upper-middle and noble classes who would form the next generation of Catholic mothers in post-Revolutionary France. The Society opened its first school at Amiens in 1801.
Madeleine Sophie served as Superior General of the Society for sixty-three years (1802–65) — through the entire 19th-century social transformation. Under her direction the Society opened over 100 schools across France, England, Italy, Belgium, the United States (Rose Philippine Duchesne's foundations from 1818 — see her entry), and Latin America. The Sacred Heart schools became, by the late 19th century, the principal Catholic boarding schools for the formation of Catholic women of the European and American Catholic upper classes. She died at the Hôtel Biron in Paris on May 25, 1865. Canonized 1925.