Leocadie attended the local parish school and spent most of her early life at home taking care of her family.
[1] She joined Father Basile Moreau in 1841 to found the Marianite Sisters of Holy Cross at Le Mans.
Gascoin pronounced first vows in 1844 and the following year Moreau made Mother Marie des Sept-Douleurs superior of the Marianite Sisters at Saint-Laurent on Montreal Island.
[3] In 1857, she was appointed superior general of the entire congregation of Marianite Sisters of Holy Cross, in France, the United States, and Lower Canada.
[2] Marie des Sept-Douleurs remained superior general of her community's houses in France and Louisiana until her death on 29 Jan.