Mary F. Platt

Mary Platt has significant experience representing clients in individual cases and class actions pending before trial and appellate courts. She has handled matters involving contract claims, shareholder and partner disputes, antitrust claims, intellectual property, restrictive covenants, trade secret misappropriation, consumer protection and unfair competition claims, employment claims, real estate and environmental issues, insurance coverage, construction disputes, toxic tort and product liability claims, and attorney malpractice claims.

Mary has represented individuals and companies ranging from closely-held businesses to large global companies in a variety of industries, including the technology, pharmaceutical, chemical, oil and gas, and real estate industries. She also has represented attorneys in disputes arising from the attorneys’ withdrawal from their firms. Mary has served as a mediator in many cases, and represented clients in litigation involving large electronic document productions. As a Judge Pro Tem in the Philadelphia Court of Common Pleas Commerce Court Program, she is frequently asked by Commerce Court Judges to hold settlement conferences for their cases.

Mary Platt became Chancellor-Elect of the Philadelphia Bar Assn. this year and will serve as Chancellor of the Philadelphia Bar Assn. in  2018. She has held several leadership positions at the Philadelphia Bar Association, including chair of the Law Practice Management Division, and chair of the Federal Courts, City Policy, and Women in Profession Committees. She has served on Bar committees that have commented on proposed amendments to the Federal Rules of Civil Procedure and the Local Rules of the United States District Court for the Eastern District of Pennsylvania. Mary served for several years as a member of the Board of Trustees of the Women’s Law Project, a non-profit focused on advancing the rights of women and girls, and volunteers for other non-profit organizations.

Mary is an honors graduate of Mount Holyoke College and Georgetown University Law Center.  Mary started her legal career at Montgomery, McCracken, Walker & Rhoads, LLP in Philadelphia, where she was an equity partner for twenty-two years, a vice chair of the Litigation Department, and a member of the Professional Responsibility Committee and Technology Committee.

Representative Matters

  • Represented a major oil company in a class action and hundreds of individual cases alleging personal injury and property damage arising from environmental contamination.
  • Represented a major software company in a class action arising from an allegedly defective product.
  • Represented a major telecommunications company in resolving a dispute with its landlord and general contractor over a significant construction defect at the client’s facility.
  • Negotiated separation agreement for a law firm shareholder.
  • Represented a specialty chemical company with respect to a third party subpoena seeking trade secrets and other confidential information pursuant to 28 U.S.C. § 1782.
  • Negotiated a separation agreement for a general counsel of a biotechnology company.
  • Served as counsel to a major software company in antitrust class actions brought by indirect purchasers of the company’s software in several states and Canada.
  • Represented major image distribution company in intellectual property litigation.


  • J.D., Georgetown University Law Center
    cum laude
  • B.A., Mount Holyoke College
    cum laude

Bar and Court Admissions

  • Pennsylvania
  • New Jersey
  • United States Court of Appeals for the Third Circuit
  • United States District Court for the Eastern District of Pennsylvania
  • United States District Court for the District of New Jersey
  • United States District Court for the Middle District of Pennsylvania


  • American Bar Association, Litigation Section
  • Philadelphia Bar Association
  • Philadelphia Association of Defense Counsel
  • Philadelphia Trial Lawyers Association
  • Brehon Law Society
  • The Justinian Society

Community/Civic Involvement

  • Philadelphia Bar Association, Elected Positions: Chancellor- Elect 2017, will serve as Chancellor in 2018. Assistant Treasurer – 2002, 2013, 2014; Treasurer – 2003 – 2005; Member, Board of Governors – 1999 – 2001, 2002 – 2005, 2013, 2014
  • Philadelphia Bar Association, Chancellor’s Cabinet – 2002 – 2005, 2008, 2013, 2014
  • Judge Pro Tem, Commerce Court, Court of Common Pleas of Philadelphia – 1995 – 2014
  • Volunteer, Women’s Business Enterprise Council – 2011 – 2014
  • Volunteer, Philadelphia Volunteers for the Indigent Program – 1998 – 1999, 2001, 2005 – 2010, 2012 – 2014
  • Chair, Justice Brennan Distinguished Jurist Award Committee – 2003; Member – 2013
  • Co-Chair, Law Practice Mgmt. Div. – 2009, 2010; Vice Chair – 2008; Treasurer – 2007
  • Co-Chair, City Policy Committee – 2007, 2008
  • Chair, Fidelity Bank (now PNC) Award Committee – 2007
  • Chair, Civility Code Task Force – 2000
  • Chair, Federal Courts Committee – 2000; Vice Chair – 1999
  • Co-Chair, Committee on Women in the Profession – 1997, 1998
  • Co-Chair, Sandra Day O’Connor Award Committee – 1997, 1998


  • Selected for inclusion in Pennsylvania Super Lawyers® – 2006-07, and each consecutive year since 2012
  • Selected by SmartCEO Magazine’s Legal Elite Readers Poll – 2011, 2012
  • Pennsylvania Bar Association Special Achievement Award – 1999

Selected Publications