David Callahan, former Global Chair of the firm's Intellectual Property Practice, represents clients in complex litigation in the areas of patent, trade secret, false advertising, and unfair competition.

Mr. Callahan represents clients in a range of industries, including medical devices, semiconductors, consumer products, telecommunications, and automotive products.

He develops winning strategies for clients based on his more than 30 years of experience as a trial lawyer, litigating bench and jury trials, as well as before the Federal and Seventh Circuit Courts of Appeal.


Leading industry publications regularly recognize Mr. Callahan’s skill and accomplishments in intellectual property. Representative accolades include:

  • 2022 IAM Patent 1000 ranked Gold for Illinois Intellectual Property Litigation
  • 2021 Law360 MVP for Intellectual Property
  • 2011 – 2022 Chambers USA ranked for work in Intellectual Property
  • 2021 – 2022 Chambers USA ranked Band 1 in Illinois for Intellectual Property: Trademark, Copyright & Trade Secrets
  • 2019 Managing Intellectual Property’s Outstanding IP Litigator of the Year in Illinois
  • 2014, 2018 BTI Consulting Group’s Client Service All-Star List, which recognizes leaders in superior client service identified exclusively by corporate counsel
  • 2020 The Best Lawyers in America recognized for work in Litigation-Intellectual Property law
  • 2015, 2017 – 2021 The Legal 500 US Recommended Lawyer for work in Intellectual Property
  • 2017 – 2021 IAM Patent 1000 ranked
  • 2012 – 2020 LMG Life Sciences listed as a star for General Patent Litigation and Hatch-Waxman Patent Litigation
  • 2010 IP Law and Business named as one of the Top 50 Under 45 IP lawyers in the country
  • 2005, 2007 – 2021 Law and Politics listed as an Illinois Super Lawyer


Mr. Callahan is a board member of Lawyers for the Creative Arts and the Public Interest Law Initiative, and serves on the board of two youth hockey organizations. He also recently served as a member of the firm’s Recruiting Committee.

Mr. Callahan’s patent litigation experience includes representing clients in the following cases:


  • AlphaSense in AlphaSense, Oy and AlphaSense, Inc. v. Tegus, Inc. and Bamsec, LLC, in the District of Delaware, in a pending case involving the defense of seven patent cases related to user interfaces for financial search software.
  • M*Modal in two patent cases involving 14 patents related to voice recognition systems.
  • FotoNation in the Eastern District of Texas in an eight-patent case related to face recognition, tracking, and photo adjustment technology used in camera phones.
  • Mallinckrodt in 10-patent ANDA litigation related to nitric oxide therapies and devices; also in five related IPR proceedings. Secured wins in all cases following trial.
  • Zimmer in Howmedica Osteonics v. Zimmer and Smith & Nephew, a four-patent action related to highly crosslinked polyethylene widely used in artificial joints. Argued and won summary judgment of indefiniteness on three patents on behalf of both defendants. Won reexamination proceedings on fourth patent and secured award of US$14 million in “exceptional case” proceeding. Won two appeals to Federal Circuit.
  • Baxter and DEKA in Baxter Healthcare and DEKA v. Fresenius as lead counsel in asserting a nine-patent portfolio related to automated peritoneal dialysis systems. Following claim construction, defendant entered into consent injunctions on five of nine patents at issue.*
  • Hill-Rom, a leading manufacturer of hospital beds and mobility systems, as lead counsel, in Hill-Rom v. Stryker; a case that involved 15 patents in two separate cases. First case settled on favorable terms to client following focused fact discovery. Successfully argued appeal in second case on claim construction issues; see Hill-Rom v. Stryker, No. 13-1450 (Fed. Cir. June 27, 2014).* 
  • Cleversafe, Inc. v. Amplidata, Inc. (closed 01/29/2015)
  • RLIS, Inc. v. Allscripts Healthcare Solutions, Inc. (closed 03/24/2015)
  • Hemopet v. Hills Pet Nutrition Inc. (closed 11/24/2014)
  • Weger v. Dyson, Inc. (closed 11/20/2014)
  • Asher v. Colgate-Palmolive Company (closed 09/14/2012)
  • Ronald A Katz Technology Licensing L P v. Progress Energy Inc et al (closed 07/30/2014)
  • Asher v. Colgate-Palmolive Company (closed 12/20/2012)

Other IP

  • LG Chem in LG Chem v. SK Innovation as lead counsel in its trade secrets dispute with competitor SK Innovation related to alleged misappropriated trade secrets relating to a broad array of LG Chem’s technological innovation related to lithium ion battery packs for electric automobiles. The US$1.8 billion settlement was one of the largest trade secret settlements ever; obtained a default judgment against SKI, as a sanction for widespread document spoliation and violation of a court order related to the forensic investigation of that spoliation.
  • Tom’s of Maine in three class-action litigations involving “natural” claims made concerning Tom’s personal care products.
  • Dyson in false advertising litigation related to vacuum cleaner performance. Won summary judgment of false advertising, following which the case settled on terms very favorable to client.*
  • Dyson in false advertising and breach of contract litigation. Won summary judgment on breach of contract claim. Case settled on eve of trail on terms very favorable for client.*

*Matter handled prior to joining Latham

Bar Qualification

  • District of Columbia
  • Illinois


  • J.D., University of Michigan Law School, 1991
  • AB, University of Chicago, 1987
    with honors
  • AA, Campbell University, 1984