William Flachsbart

Phone: 312-551-9500

Email: wflachsbart@dbllawyers.com

Office: Chicago IL

Practice Areas
  • Complex Litigation
  • Intellectual Property Litigation
  • Negotiation
  • Business Contracts
  • Appeals
  • Mediation and Arbitration
Awards and Honors
  • Award for Excellence in Pro Bono Service, United States District Court for the Northern District of Illinois May 14, 2015
  • Illinois Super Lawyer (Intellectual Property) 2013-2022

William Flachsbart


William Flachsbart is a Partner at Dunlap Bennett & Ludwig. Mr. Flachsbart provides counsel regarding a wide array of legal matters to both high-tech companies and individuals, including patent, trade secret, and trademark issues. Mr. Flachsbart assists companies and individuals in preparing to litigate and defend intellectual property claims. Mr. Flachsbart also has extensive experience dealing with non-disclosure and non-competition agreements and with assisting companies in assessing complicated intellectual property structures to determine the scope of their assets or exposure, including evaluation of patents, trade secrets, and publicly available information.

Mr. Flachsbart also has a broad base of litigation experience at all stages of trial preparation and trial, from pre-filing investigation and analysis through all of the stages of discovery, trial, and appeal. He has substantial defense experience and has resolved multimillion-dollar claims while representing defendants and plaintiffs alike.

  • J.D., Loyola University Chicago School of Law
  • M.S., Mathematics, University of Oregon
  • S.B., Mathematics with a concentration in Computer Science, University of Chicago
  • Illinois 11/07/96
  • Supreme Court of Illinois 11/07/96
  • N.D. Illinois, December 18, 1996
  • D. Arizona, January 25, 2000
  • E.D. Tennessee, February 2, 2000
  • U.S. Court of Appeals for the Federal Circuit, March 21, 2000
  • D. Colorado, February 11, 2002
  • W.D. Wisconsin, February 3, 2003
  • D. Minnesota, March 7, 2005
  • Supreme Court of the United States, June 22, 2009
  • D. Connecticut, September 14, 2012
  • U.S. Court of Appeals for the 7th Circuit, January 30, 2015
  • U.S. Court of Appeals for the 8th Circuit, February 15, 2017
  • W.D. New York March 7, 2019
  • Mr. Flachsbart’s primary focus is on commercial litigation, including intellectual property and contract or other business disputes. He has managed individual patent lawsuits, run large-scale licensing campaigns, and has assisted clients with a wide variety of business disputes in either resolving them without resort to the courts or in litigating where such efforts became necessary.
  • Mr. Flachsbart has coordinated multiple IP portfolio licensing campaigns for IP portfolios including: a campaign for frequency and protocol agile wireless and cellular devices, which included filing multiple lawsuits in the Eastern District of Virginia on behalf of one of the inventors and his company; a campaign relating to leveraging mobile devices for mapping of branded locations which included multiple lawsuits in the Northern District of Illinois, and a wide range of additional lawsuits filed in federal courts across the country.
  • Mr. Flachsbart argued and won a white-collar criminal sentencing appeal in United States v. Pu, 814 F.3d 818 (7th Cir. 2016).
  • Mr. Flachsbart worked with Mr. Greenspoon in successfully appealing a finding of inequitable conduct in 1st Media v. Electronic Arts, et. al., 694 F.3d 1367 (Fed. Cir. 2010), and has worked with Mr. Greenspoon on a wide variety of successful appeals to the Federal Circuit and other federal appellate courts.
  • Mr. Flachsbart and Mr. La Porte (also of the firm) represented an inmate in an Eighth Amendment case on a pro bono basis and won a jury trial in Curry v. Weathersby, 11-CV-5590 (N.D. Illinois), in which the jury found that the defendant prison guard had violated the inmates civil rights and awarded punitive damages.
  • Mr. Flachsbart represented a doctor who was sued by another doctor under trademark law as a result of the similarity in their names in Joshi v. Joshi, 18-cv-05426 (N.D. Illinois).
  • Mr. Flachsbart has also successfully resolved matters without resort to the courts, including multiple non-competition and trade secret disputes, and successfully negotiated the resolution of a breach of contract case based on a significant acquisition offer later reneged on.
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