Mary joined DeLeon & Stang in 2014 and currently serves as a Senior Accountant.  Having earned a QuickBooks Pro-Advisor Certification (2011-2013), she has done a lot of work with small, family run businesses in various industries.

Self-described as honest, she is considered cooperative by her peers.  Mary holds herself to a higher standard when it comes to customer service, with regard to both internal and external communications.  She attributes her success to her desire to learn new things and help others.  With a love of playing with a cash register and play money as a child, along with an influence from her a high school teacher, Mary gravitated toward the accounting profession.

A favorite quote of hers is from a poem called Desiderata by Max Ehrmann: “As far as possible without surrender be on good terms with all persons.”

In her leisure time, Mary enjoys studying railroad history, running American Flyer train equipment, reading, cooking and stained glass cutting.  She is proud to have served on the Gaithersburg St. Patrick’s Day Parade committee for 17 years (since the inaugural event in 2001), 15 of those years she held the role of chairperson.

Having grown up in Martinsburg, West Virginia, she now resides in Boyds, Maryland with her husband, Tracy Schaff, and their two cats.


Fun Fact:

Mary loves to throw parties! At her annual St. Patrick’s Day party, she prepares 55+ lbs of corned beef for up to 70 guests.


  • Certified Public Accountant
  • QuickBooks Pro-Advisor


  • American Institute of Certified Public Accountants (AICPA)
  • Maryland Association of Certified Public Accountants (MACPA)
  • Maryland Society of Accounting and Tax Professionals (MSATP)
  • Shepherd University Alumni Association
  • Gaithersburg HELP Organization
    • Treasurer and Board of Directors


  • Shepherd College (Now known as Shepherd University)
    • Bachelor of Science in Business Administration – Accounting Concentration
    • Minor in Computer Science