Ms. McMahon was born in Grand Haven Michigan. She has undergraduate degrees from the University of Michigan and Antioch College.
Ms. McMahon attended the University of Toledo College of Law and she graduated from Wayne State University College of Law with a Juris Doctorate Degree in 1979. She is a member of Phi Alpha Delta and served as Vice Justice, Coke Chapter, 1977 - 1978. She was also a member of the University of Toledo Law Review from 1977 - 1978 and authored "Eliminating Diversity Jurisdiction: A Short-Term Solution to a Long-Term Problem", 9 University Toledo Law Review 869 (1978.)
Ms. McMahon created a two volume publication, Michigan Probate Sourcebook: Statutes, Rules and Forms for Estate Administration, for the Institute of Continuing Legal Education. She also edited Michigan Independent Probate and How to Probate an Estate Under $600,000.
Ms. McMahon was admitted to practice in Florida in 1981. She is Board Certified in Wills, Trust & Estates (Florida Bar Board of Legal Specialization & Education.) Ms. McMahon is also licensed to practice in Michigan, Colorado, and before the U.S. District Court; E.D. Michigan and U.S. 6th Circuit Court of Appeals. She is a member of the State Bar of Michigan and the Florida Bar (Member and Vice Chair, Continuing Legal Education Committee, 1985 - 1995, and member of the Wills, Trusts & Estates Certification Committee, 1999 - 2002.)
Ms. McMahon is a member of the Real Property, Probate and Trust Law Section and Elder Law Section of the Florida Bar. She is also a member of the Southwest Florida Estate Planning Council.
In 2012, Ms. McMahon was named a Sarasota Five Star Wealth Manager and a 2012 Martindale-Hubbell Top Lawyer in Sarasota and Manatee Counties. Ms. McMahon resides in Bradenton, Florida.