In 1949 the word "Charity" was added to the congregation's name, in order to identify it more explicitly with others that follow the Rule of Life of St. Vincent de Paul.
While attending the first Provincial Council of Baltimore in the fall of 1829, England met four women of that city: sisters Mary and Honora O’Gorman, their niece, Teresa Barry (aged 15), natives of Ireland and Mary Elizabeth Burke, who all wished to live a consecrated life dedicated to serving the poor, sick, orphaned and uneducated in his diocese.
They operated a number of educational and medical institutions which lasted for varying periods, including a school for the children of free blacks.
Consequently, when new dioceses were established for Savannah, Georgia, and Wilmington, North Carolina, the Sisters living in those locations were separated from the motherhouse in Charleston, coming under the authority of the new local bishops.
In the wake of Hurricane Hugo, Sister Carol Wentworth established the Nun Better Roofing Company; all work was free of charge.
As of 2014 fifteen Sisters of Charity of Our Lady of Mercy serve Charleston, South Carolina from the May Forrest motherhouse on James Island.