Diane Siegel Danoff


Diane Siegel Danoff


Philadelphia | Cira Centre, 2929 Arch Street, Philadelphia, PA, United States of America 19104-2808
+1 215 994 2179 | +1 215 994 2222


Diane Siegel Danoff is a nationally recognized litigator in our Intellectual Property Group and heads the group’s global Trade Secret Litigation practice. She has extensive litigation experience, developed during over 30 years of practice, with trade secret, non-compete, trademark, patent, copyright, unfair advertising, and invasion of privacy matters. She has litigated cases covering highly sophisticated technologies such as medical devices, web-based technologies, specialty chemicals, financial services, and semiconductor packaging, as well as various commercial litigation matters. Ms. Danoff frequently handles injunctions and, in one case in federal court, won a highly unusual award of attorneys’ fees at the temporary restraining order stage of the case.

Ms. Danoff has been named ten times as a leading litigator by Chambers USA, a referral guide to leading lawyers in the United States. Chambers has called her “superb, thorough and decisive” and “recommended for her courtroom skills.” In addition, she is listed in The Legal 500 US, is recognized by The Best Lawyers in America for Intellectual Property and Patent Litigation, and, in 2017, earned the "Lawyer of the Year" distinction for Trade Secrets law.  In 2015, Ms. Danoff was named a BTI Client Services All-Star, recognized as one of 25 IP lawyers nationwide for excellence in client service and “having a deep awareness of the interplay between the complicated technical, legal and business issues facing IP clients.” In 2020, she was named an "IP Star" for both trademark and copyright by Managing Intellectual Property.

In 2017, Ms. Danoff was awarded the Arthur Seidel Distinguished IP Service Award by the IP Law Institute of the Pennsylvania Bar Institute.  She has also been a core member of the Dechert team named “IP Litigation Department of the Year” for Pennsylvania by the Legal Intelligencer three times in recent years.  

  • Represented Microsoft Corp. and a prospective Microsoft executive in a non-compete/trade secret litigation by an international technology company against the executive. Resolved favorably to Microsoft and the executive.
  • Defended SGS International Inc. in a $25 million trade secret case involving alleged misappropriation of trade secret printing techniques in the making of Tervis Tumblers drinkware, obtaining voluntary dismissal before trial in complete walkaway, with no payment of damages or injunction. 
  •  Defended European private equity firm in trademark litigation with major hedge fund in the U.S. District Court for the Southern District of New York. 
  • Represented leading semiconductor packaging company in trade secret, copyright and patent litigation claiming over $90 million in damages. Settled favorably to client. 
  • Obtained preliminary injunction for WebMD following four-day evidentiary hearing in trade secret and non-compete case involving former high-level executive.
  • Defended Uptime Institute in trademark and false advertising case in the D. Nevada involving data centers.  
  • Represented leading medical device company plaintiff in a trade secret and Lanham Act case involving medical devices for the spine. Resolved by a US$13.5 million payment to our client (and an agreement not to solicit our client’s employees) following a two-week jury trial.
  • Represented MetLife in business method patent case and separate trade secret action involving a method of funding insurance products. Obtained complete victory before trial court which was affirmed on appeal.
  • Represented Kellogg Co. and Nintendo in trademark/unfair competition suit involving a Pokémon® promotion on Kellogg’s® cereal boxes. Settled favorably to our clients.
  • Represented the leading U.S. dry pasta maker in Lanham Act case involving our client’s Ronzoni®, San Giorgio®, Prince® and Creamette® packaging. Settled favorably to our client.
  • Represented international package forwarding business in major copyright and trade secret lawsuit. Settled favorably to client. 
  • Defended “Rocket Docket” patent/antitrust suit brought by Anheuser-Busch Companies against Crown Cork and Seal Co., involving aluminum can lids. Resolved by a Federal Circuit ruling for our client on certain counts and a settlement favorable to our client on the remaining counts.
  • Represented Tribune Entertainment in non-compete case involving nationally broadcast program. Defeated plaintiff’s preliminary injunction motion following full evidentiary hearing. After that ruling, plaintiff dropped the case without any settlement.
  • Represented Kofax in a false advertising case filed pursuant to the Lanham Act, and in companion trade secret/non-compete case, in the “Rocket Docket” of the U.S. District Court for the Eastern District of Virginia. Settled favorably to our client.
  •  Represented Bank of New York Mellon in non-compete and trade secret litigation against former employee and investment advisory firm, in court and before FINRA. Settled favorably to our client.
  • Defended WebMD in Lanham Act case regarding website publication. Settled favorably to our client.
  • Defended Dow Chemical Co. subsidiary, in suit arising out of a trade secret misappropriation litigation. Obtained complete dismissal by trial court and complete affirmances on appeal.
  • Defended WPIX-TV in invasion of privacy litigation involving Public Service Announcement. Obtained voluntary dismissal without settlement following discovery.
  • Harvard University, A.B., 1981, magna cum laude, Phi Beta Kappa
  • The University of Chicago Law School, J.D., 1984
  • Pennsylvania
  • Illinois
  • United States District Court for the Eastern District of Pennsylvania
  • United States Court of Appeals for the Third Circuit
  • United States District Court for the Northern District of Illinois
  • United States District Court for the Western District of Pennsylvania
  • Supreme Court of the United States
Ms. Danoff has served as a sub-committee Chair of the American Bar Association’s committee on Trade Secrets and Interference with Contracts and also the committee on Non-Compete Agreements.
She has also served as a member of the Merit Selection Panel for the selection of a U.S. Magistrate Judge for the United States District Court for the Eastern District of Pennsylvania. 
In addition, Ms. Danoff is a past Chair of the Board of Philabundance, a non-profit that gathers surplus food for the needy in the Delaware Valley.
Speaking Engagements
  • External Investigations: When is it Okay to Pretend? – Greater Philadelphia ACC (American Corporate Counsel) 11th Annual In-House Counsel Conference, Philadelphia, PA (April 24, 2019)
  • Trade Secret Update, 13th Annual Intellectual Property Law Institute – Pennsylvania Bar Institute, Philadelphia, PA (April 16, 21019)
  • Trading on Trade Secrets: What Financial Services Information is Protectable, Intellectual Property Issues in Financial Services Seminar: What's Hot? — Boston, MA (September 27, 2018)
  • Waymo v. Uber: DTSA Test Tube — IPO IP Chat Channelwebinar, Intellectual Property Owners Association (March 15, 2018)
  • Lessons from the Waymo (Google)/Uber Self-Driving Car Case, For All Litigators — Greater Philadelphia ACC (American Corporate Counsel) 10th Annual In-House Counsel Conference, Philadelphia, PA (April 25, 2018)
  • Trade Secret Update, 12th Annual Intellectual Property Law Institute — Pennsylvania Bar Institute, Philadelphia, PA (April 24, 2018)
  • Trade Secret Update, 11th Annual Intellectual Property Law Institute — Sponsored by the Pennsylvania Bar Institute, Philadelphia, PA (April 26, 2017)
  • The New Federal Trade Secret Law and Other Recent Developments in the Law of Trade Secrets and Non-Competes — 22nd Annual Business Law Institute, Pennsylvania Bar Institute, Philadelphia, PA (November 16, 2016)
  • The Ethics of Pretexting in Investigations of Trade Secret Theft and Other IP Violations — Philadelphia Intellectual Property Law Association Year End Meeting, Philadelphia (May 3, 2016)
  • Trade Secret Update — Intellectual Property Law Institute sponsored by the Pennsylvania Bar Institute, Philadelphia (April 29, 2015)
  • Restraining Orders and Preliminary Injunctions — Commercial Litigation Institute sponsored by the Pennsylvania Bar Institute, Philadelphia (March 18, 2015)
  • Women in IP Law Breakfast panel on effective communications with clients — American Intellectual Property Law Association Spring Meeting, Philadelphia, PA (May 16, 2014)
  • Trade Secret Update, 8th Annual Intellectual Property Law Institute — Pennsylvania Bar Institute, Philadelphia, PA (April 8, 2014)
  • Protecting Your Trade Secrets Before It's Too Late — Association of Corporate Counsel - Greater New York Chapter, New York, NY (September 18, 2013)
  • Trade Secret and Non-Compete Update — DELVACCA, Philadelphia, PA (June 4, 2013)
  • Trade Secret Update — Philadelphia Intellectual Property Law Association, Philadelphia, PA (May 14, 2013)
  • Recent Developments in Trade Secret Law — Pennsylvania Bar Institute, Philadelphia, PA (April 25, 2013)