• James Madison University (B.A., cum laude, 1999)
  • George Washington University Law School (J.D., 2002)


  • District of Columbia and Virginia
  • United States Supreme Court
  • United States Courts of Appeals for the Tenth, District of Columbia, and Federal Circuits
  • United States District Courts for the District of Maryland, Western District of Tennessee, Eastern District of Texas, and Eastern and Western Districts of Virginia


Ann Marie Duffy has broad experience in the defense of complex civil litigation, including commercial, medical device, fraud, and intellectual property cases.  She has substantial trial and oral argument experience, having first-chaired a breach of contract trial and second-chaired others, including a patent trial in the District Court of Delaware in a case where total damages exceeded $2 billion.  During the patent trial, Ms. Duffy directed and crossed witnesses, argued numerous evidentiary disputes and final jury instructions, and managed the trial war room, including daily trial deadlines.  Ms. Duffy has also worked on numerous breach of contract cases and matters that have involved claims for tortious interference, civil conspiracy, trade libel, and theft of trade secret.  Ms. Duffy has also briefed and argued appeals to the United States Court of Appeals for the Tenth Circuit and the United States Court of Appeals for the District of Columbia Circuit.

Ms. Duffy’s broad range of litigation experience includes working on highly complex cases with significant discovery and procedural issues.  Her cases have routinely involved large numbers of document custodians and fact witnesses as well as multi-national discovery efforts.  Ms. Duffy also has extensive experience working with experts across various fields, preparing reports, preparing for and taking expert depositions, and preparing trial testimony.

In addition to her trial experience, Ms. Duffy has litigated cases across the country, including in the Eastern District of Virginia, District of Delaware, Central District of California, Eastern District of Pennsylvania, District of Maryland, Southern District of New York, Northern District of Ohio, Western District of Virginia, Eastern District of Texas, and Western District of Tennessee.