Kevin J. O'Brien

Kevin O’Brien is an experienced intellectual property litigator. He has represented clients through all stages of patent litigation matters, including trial, appeal and pre-litigation investigation. Mr. O’Brien has also represented clients in IP antitrust, FRAND, trade secret and trademark cases. His experience ranges across technical fields, including smartphones, 4G/LTE, information technology, integrated circuits, small molecule pharmaceuticals, large molecule biologics, medical devices and consumer goods.

Mr. O’Brien is experienced in managing cases through fact and expert discovery. He has taken and defended over a dozen fact depositions. Mr. O’Brien also has extensive experience with technical and economic experts, including taking and defending expert depositions. In federal court, Mr. O’Brien has argued motions to dismiss, discovery motions, a motion to consolidate patent infringement actions, a motion to strike an expert report, a motion to exclude an expert witness and numerous pre-trial and trial evidentiary disputes. Mr. O’Brien also specializes in writing complex briefs, including briefs for claim construction, summary judgment, Daubert and post-trial briefs. Mr. O’Brien has trial cross-examination experience.

Before joining WilmerHale, Mr. O’Brien served as an associate at two other large law firms.

Mr. O’Brien has also served as the contributing editor to the 2016 and 2012–2014 editions of The Rutter Group Practice Guide: Federal Civil Procedure Before Trial.



  • Represented a major pharmaceutical company in multiple patent suits involving replacement Factor VIII biologic products used to treat hemophilia. (D. Del.) Mr. O’Brien was a member of a trial team that won a $155 million patent infringement verdict in his client’s favor.
  • Represented a major smartphone company in a patent infringement and FRAND action involving 4G/LTE technology. (N.D. Cal.)  
  • Representing an online luxury clothing consignment retailer in a misappropriation of trade secrets action against an international competitor. (C.D. Cal.) Case favorably settled.
  • Represented a major smartphone company in a patent infringement case involving integrated circuits and power management technology. (E.D.T.X.) Case favorably settled after winning a key motion to exclude all pre-suit damages based on a failure to mark defense.
  • Represented a premier enterprise information technology company defending a seven-patent infringement suit involving database access technology. (N.D. Cal.) The case was resolved with a successful motion for summary judgment of non-infringement of all remaining asserted claims.
  • Represented a leading provider of one-time programmable non-volatile memory in multiple cases against a competitor involving a patent infringement defense and an affirmative antitrust claim. (N.D. Cal.) After winning summary judgment of non-infringement for all claims and obtaining an attorney’s fees award of more than $5 million under the exceptional case doctrine, the client obtained a favorable global settlement of all pending matters.
  • Represented a publicly traded pet supplies company in a defense of a patent infringement action that included successfully defending a motion for a preliminary injunction. (D. Del.)
  • Represented a national print and digital advertising company against a competitor in a defense of claims under the California Unfair Practices Act for illegal below-cost pricing and unearned secret discounts. (Cal. Superior Court.) Case settled favorably.
  • Represented an international semiconductor manufacturer in a defense to patent infringement claims related to semiconductor packaging technology. (D. Del.)


  • Recognized as a "Rising Star" by Super Lawyers in 2019 and 2020

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  • Education

    • JD, University of California, Hastings College of Law, 2011

      summa cum laude 

      Symposium Editor, Hastings Law Journal, Order of the Coif
    • BA, English Literature, University of California, Santa Barbara, 2007

  • Admissions

    • California

  • Clerkships

    • The Hon. Richard Andrews, US District Court for the District of Delaware, 2012 - 2013