William W. Flachsbart

William W. Flachsbart

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William Flachsbart is a founding member of Flachsbart & Greenspoon, LLC. Mr. Flachsbart provides counsel regarding a wide array of technology and intellectual property 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 including patents, trade secrets, and publicly available information.

Mr. Flachsbart also has significant experience in the litigation and trial of patent cases involving computer, network, electronic, and emerging technologies. Mr. Flachsbart has experience at all stages of trial preparation and trial, from pre-filing investigation and patent portfolio analysis through all of the stages of discovery, trial, and appeal. Mr. Flachsbart's experience includes Markman hearings, pre-trial preparation, trial, and management of licensing campaigns for patentees, trademark owners, and trade secret holders, among others. He also has substantial defense experience and has resolved multimillion-dollar claims while representing accused infringers. Mr. Flachsbart has a wide variety of experience participating in mediation and settlement negotiation in addition to his litigation background.

Mr. Flachsbart is comfortable in a courtroom and cogently and persuasively presents both legal issues and complex technology. One client praises Mr. Flachsbart's performance in a courtroom by describing his "commanding presence," highlighting "his articulate, passionate delivery," and his combination of "knowledge, strategy and presentation skills." Another speaks of Mr. Flachsbart's "impressive skills and tenacious efforts" on his behalf.

Mr. Flachsbart is a co-author of "Obviousness after KSR v. Teleflex: A Private Practice Perspective," in the August/September 2007 issue of Intellectual Asset Management Magazine, reprinted in the July/August issue of IP Litigator.


Mr. Flachsbart obtained his S.B. degree in Mathematics with a concentration in Computer Science from the University of Chicago. He received his M.S. in Mathematics from the University of Oregon. He received his J.D. degree at the Loyola University Chicago School of Law.


Mr. Flachsbart is a member of the ABA. Mr. Flachsbart is also an adjunct faculty member at the DePaul University College of Law, where he teaches Intellectual Property Litigation Strategy. Mr. Flachsbart also teaches classes on the Constitution to 7th Graders at the Goudy School, a CPS school on Chicago's North Side.