The childhood of Julie was remarkable; at the age of seven, she knew the catechism by heart, and used to gather her little companions around her to hear them recite it and to explain it to them. Her education was confined to the rudiments obtained at the village school which was kept by her uncle, Thibault Guilbert. In spiritual things her progress was so rapid that the parish priest, M. Dangicourt, allowed her to make her First Communion and to be confirmed at the age of nine years. At this time she made a vow of chastity. Misfortunes overtook the Billiart family when Julie was sixteen, and she gave herself generously to the aid of her parents, working in the fields with the reapers. She was held in such high esteem for her virtue and piety as to be commonly called, "the saint of Cuvilly". When twenty-two years old, a nervous shock, occasioned by a pistol-shot fired at her father by some unknown enemy, brought on a paralysis of the lower limbs, which in a few years confined her to her bed a helpless cripple, and thus she remained for twenty-two years. During this time, when she received Holy Communion daily, Julie exercised an uncommon gift of prayer, spending four or five hours a day in contemplation. The rest of her time was occupied in making linens and laces for the alter and in catechizing the village children whom she gathered around her bed, giving special attention to those who were preparing for their First Communion.
At Amiens, where Julie Billiart had been compelled to take refuge with Countess Baudoin during the troublesome times of the French Revolution, she met Françoise Blin de Bourdon, Viscountess of Gizaincourt, who was destined to be her co-laborer in the great work as yet unknown to either of them. The Viscountess Blin de Bourdon was thirty-eight years old at the time of her meeting with Julie, and had spent her youth in piety and good works; she had been imprisoned with all of her family during the Reign of Terror, and had escaped death only by the fall of Robespierre. She was not at first attracted by the almost speechless paralytic, but by degrees grew to love and admire the invalid for her wonderful gifts of soul. A little company of young and high-born ladies, friends of the viscountess, was formed around the couch of "the saint". Julie taught them how to lead the interior life, while they devoted themselves generously to the cause of God and His poor. Though they attempted all the exercises of an active community life, some of the elements of stability must have been wanting, for these first disciples dropped off until none was left but Françoise Blin de Bourdon. She was never to be separated from Julie, and with her in 1803, in obedience to Father Varin, superior of the Fathers of the Faith, and under the auspices of the Bishop of Amiens, the foundation was laid of the Institute of the Sisters of Notre Dame, a society which had for its primary object the salvation of poor children. Several young persons offered themselves to assist the two superiors. The first pupils were eight orphans. On the feast of the Sacred Heart, June 1, 1804, Mother Julie, after a novena made in obedience to her confessor, was cured of paralysis. The first vows of religion were made on October 15, 1804 by Julie Billiart, Françoise Blin de Bourdon, Victoire Leleu, and Justine Garson, and their family names were changed to names of saints. They proposed for their lifework the Christian education of girls, and the training of religious teachers who should go wherever their services were asked for. Father Varin gave the community a provisional rule by way of probation, which was so far-sighted that its essentials have never been changed. In view of the extension of the institute, he would have it governed by a superior-general, charged with visiting the houses, nominating the local superiors, corresponding with the members dispersed in the different convents, and assigning the revenues of the society. The characteristic devotions of the Sisters of Notre Dame were established by the foundress from the beginning. She was original in doing away with the time-honored distinction between choir sisters and lay sisters, but this perfect equality of rank did not in any way prevent her from putting each sister to the work for which her capacity and education fitted her. She attached great importance to the formation of the sisters destined for the schools, and in this she was ably assisted by Mother St. Joseph (Françoise Blin de Bourdon), who had herself received an excellent education.
When the congregation of the Sisters of Notre Dame was approved by an imperial decree dated June 19, 1806, it numbered thirty members, In that and the following years, foundations were made in various towns of France and Belgium, the most important being those at Ghent and Namur, of which the latter house Mother St. Joseph was the first superior. This spread of the institute beyond the Diocese of Amiens cost the foundress the greatest sorrow of her life. In the absence of Father Varin from that city, the confessor of the community, the Abbé de Sambucy de St. Estève, a man of superior intelligence and attainments but enterprising and injudicious, endeavored to change the rule and fundamental constitutions of the new congregation so as to bring it into harmony with the ancient monastic orders. He so far influenced the bishop, Monsenginor Demandolx, that Mother Julie had soon no alternative but to leave the Diocese of Amiens, relying upon the goodwill of Msgr. Pisani de la Gaude, bishop of Namur, who had invited her to make his episcopal city the center of her congregation, should a change become necessary. In leaving Amiens, Mother Julie laid the case before all her subjects and told them they were perfectly free to remain or to follow her. All but two chose to go with her, and thus, in the mid-winter of 1809, the convent of Namur became the motherhouse of the institute and is so still. Msgr. Demandolx, soon undeceived, made all the amends in his power, entreating Mother Julie to return to Amiens and rebuild her institute. She did indeed return, but after a vain struggle to find subjects or revenues, went back to Namur. The seven years of life that remained to her were spent in forming her daughters to solid piety and the interior spirit, of which she was herself the model. Msgr. De Broglie, bishop of Ghent, said of her that she saved more souls by her inner life of union with God than by her outward apostolate. She received special supernatural favors and unlooked-for aid in peril and need. In the space of twelve years (1804 - 1816) Mother Julie founded fifteen convents, made one hundred and twenty journeys, many of them long and toilsome, and carried on a close correspondence with her spiritual daughters. Hundreds of these letters are preserved in the motherhouse. In 1815 Belgium was the battlefield of the Napoleonic wars, and the mother-general suffered great anxiety, as several of her convents were in the path of the armies, but they escaped injury. In January, 1816, she was taken ill, and after three months of pain borne in silence and patience, she died with the Magnificat on her lips.
The fame of her sanctity spread abroad and was confirmed by several miracles. The process of her canonization was begun in 1881. She was beatified in 1906 by the decree of Pope Pius X dated May 13, declaring her Blessed; and canonized in 1969 by Pope Paul VI, declairing her a saint.
St. Julie's predominating trait in the spiritual order was her ardent charity, springing from a lively faith and manifesting itself in her thirst for suffering and her zeal for souls. Her whole soul was echoed in the simple and naove formula which was continually on her lips and pen: Oh, qu'il est bon, le bon Dieu (How good God is). She possessed all the qualities of a perfect superior, and inspired her subjects with filial confidence and tender affection.