[4] As a young girl, the family relocated to Baton Rouge so that her father could serve in administrative posts at Louisiana State University.

McMain briefly served as a teacher in Baton Rouge before subsequently relocating to New Orleans to further her training at the Free Kindergarten Association, an Episcopal sponsored effort to provide innovations in pre-school education.

[2] The training school of the Free Kindergarten Association combined with the Trinity Church Mission to form Kingsley House.

By 1902, McMain reorganized Kingsley House on a nonsectarian basis,[1] and it thereby went from being Episcopalian to having Roman Catholic and Jewish representation on their board.

In 1912, McMain took a leave of absence from Kingsley House to visit Chicago while recovering from malaria, and renewing her relationship with Addams.

[6] In 1905, McMain led a clean-up and education campaign to help eradicate the yellow fever epidemic in the Irish Channel of New Orleans.

She lobbied the Louisiana State Legislature for child labor laws and, in 1910, achieved passage of Women's League sponsored compulsory education.

[6] During her tenure, Kingsley House established a Woodworking Class for the Blind, conducted by an instructor from the Delgado Trade School.

[4] In 1921, McMain helped establish the Tulane University School of Social Work, the fifth oldest institution of its kind in the United States.

[4] Also that year, she helped prepare the charter of the New Orleans Central Council of Social Agencies, the forerunner of the local Community Chest and later United Way, and served as its president in 1927.

[5] Through these connections, she relocated to Paris, France, for a year to help establish the L'Accueil Franco-Americain, a Parisian settlement house, founded by J. Catlin-Tauffleib, the American wife of a French General.

[4] Soon after returning to the United States, her health declined, and she died in 1934, at home at Kingsley House,[4] from heart disease complicated by hypertension.