Marsha graduated from Winter Haven, Florida, High school. She received her BA in Psychology from the University of South Florida and her MSW from Florida State University. She then taught for a year at Troy State University before being hired to become the first Director of the MSU undergraduate Social Work program. She guided that program though accreditation. In her early days in Springfield she was on the steering committee for the Child Advocacy Council and was the President of the local ACLU.
She then changed directions, left the University, and became a Certified Genealogist. In that capacity she became the President of the Genealogical Speakers Guild, the President of the Federation of Genealogical Societies, a Fellow and President of the American Society of Genealogists, the Vice-President of the National Genealogical Society and a Trustee of both the New England Historic Genealogical Society and the Association of Professional Genealogists. She published several books, the most popular of which was The Family Tree Problem Solver. She also published several genealogical references, the magnum opus being Opening the Ozarks: The First Families in Southwest Missouri.