She was the daughter of Catherine Émonnot and Charles Mance, a prosecutor for the king in Langres, an important diocese in the northern Burgundy.

Mance was a member of the Société Notre-Dame de Montréal; its goal was to convert the natives and found a hospital in Montreal similar to the one in Quebec.

Charles Lallemant recruited Jeanne Mance for the Société Notre-Dame de Montréal.

After wintering in Quebec, she and Paul Chomedey de Maisonneuve arrived at the Island of Montreal in the spring of 1642.

At the same time, she secured three Hospital Sisters of the Religious Hospitallers of St. Joseph from the convent of La Fleche in Anjou: Judith Moreau de Bresoles, Catherine Mace, and Marie Maillet.

They had a difficult passage on the return, made worse by an outbreak of the plague on board, but all four women survived.

de Laval tried to retain the sisters at Quebec for that hospital, they eventually reached Montreal in October 1659.