Her patriotism was shown in her work for the Daughters of the American Revolution (DAR) Mohawk Chapter of Albany, New York, of which she was regent.

[2] Sent by President William McKinley to Paris in 1900, he appointed her commissioner to the Exposition Universelle and to represent the U.S. and the DAR at the unveiling of the statue of Gilbert du Motier, Marquis de Lafayette (July 4, 1900).

Mary Margaretta could trace her Dutch ancestry back many generations in Holland on her father's side.

[4] On November 19, 1884, in Albany, she married Daniel Manning,[3] who, in the following March, was appointed U.S. Secretary of the Treasury under President Grover Cleveland.

Manning was a delegate to represent the society in 1900, and with Mrs. John P. Jones, of Nevada, unveiled the statue before an assembly at Place des États-Unis, Paris, on July 3.