Marsh is responsible for ending the sole guardianship laws in the state of Missouri through her persistent dedication for change.

[2] Marsh was heavily involved as a member of the Webster Groves chapter of the Daughters of the American Revolution.

Marsh was bothered by the sole guardianship law that deemed men full custody of their children and the ability to take their child's wages.

After hearing the story of a young girl in St. Louis who was forced to give her alcoholic father all of her earned money, Marsh decided to provoke change.

The Marsh Joint Guardianship Law is formally known as, Guardians and Curators of Minors-Granting Married Women Equal Rights With Husbands in Care of Minor children and Management of Their Estates.

Sixth, rights of parents equal, in custody or control of minor children, of their services and earnings-court to adjudicate.

The act also included a new law to those who are mentally unstable, known as: Guardians and Curators of Insane Persons-Facts Inquires Into by Court Sitting as a Jury.

Published in 1929, the story was meant as a persuasion to implement a proposed memorial for Lincoln and his family in Spencer, Indiana.

She is buried at Bellefontaine Cemetery in St. Louis in the same lot as her husband and other relatives including Olydia, Frank, Mildred, and Angeline Marsh.