Emmett J. McMahon



Mr. McMahon has over 30 years experience in commercial litigation with emphasis in intellectual property.  He has gained a wide level of experience in disputes that are vital to his clients, in such technologies as money transfer, stored value instruments, encryption, video and lossless compression, Wi-Fi, network-based data distribution, MRI, and DNA  sequencing and testing.   He has handled patent, copyright, trade secret, trademark, false advertising, securities and class action disputes for both plaintiffs and defendants. 

Mr. McMahon’s practice spans many district and appellate courts throughout the United States.  He has had more than 20 engagements in the Eastern District of Texas, the busiest jurisdiction for patent trials. 

Mr. McMahon was recognized as one of the “Top-Rated Lawyers in Intellectual Property Law” by the peer-rating service Martindale Hubbell.  

Mr. McMahon is active in charitable organizations.  He is a past Vice Chairman of the Board for Children’s HeartLink, a nationally known charitable organization that partners with Fortune 500 companies and promotes sustainable cardiac care for children around the world.  He is an avid tennis player, a seasoned long distance runner, and a retired black belt in the pure form of Tae Kwon Do.  When time allows, he enjoys traveling with his wife of over 30 years. 


Lead counsel for Honeywell International Inc. in a trade secret and breach of contract dispute with Ophir Corporation involving Lidar-based optical air data systems for navigating aircraft.  Settled the case on behalf of Honeywell  after previously prevailing on a motion for a temporary restraining order/preliminary injunction.  The dispute was venued in the United States District Court for the District of Arizona as Case No. CV-17-02083-PHX-GMS.

Represented Quest Diagnostics Incorporated in multi-district patent infringement litigation involving Myriad Genetics’ patents for genetic-based tests to detect genes linked to hereditary cancer.  Obtained a dismissal of all claims.   In re: BRCA1- and BRCA2-Based Hereditary Cancer Test Patent Litigation, No. 2:14-MD-02510-RJS (D. Utah).

Trial and appellate counsel for MoneyGram in Western Union Co. v. MoneyGram Payment Systems, Inc., 626 F. 3d 1361 (Fed. Cir. 2010).  The Federal Circuit Court of Appeals found in favor of MoneyGram and invalidated all asserted claims of three patents held by Western Union relating to methods of transferring money. The asserted claims of the three patents were held obvious as a matter of law.  

Trial and appellate counsel for the plaintiff in Grantley v. Clear Channel Communications, Inc. This was a patent infringement case in which a federal jury in the Eastern District of Texas awarded Grantley $66 million. The jury found that Clear Channel Communications, Inc., a direct competitor of Grantley’s sister corporation, directly infringed on four of Grantley’s patents related to an integrated inventory management system for radio advertising time. The jury also found that the infringement was willful. The district court enhanced the damages by more than $16.5 million, awarded prejudgment interest and entered judgment totaling more than $89 million. The case settled while on appeal under confidential terms.

Represented Quest Diagnostics in Prometheus Laboratories, Inc. v. Quest Diagnostics, resulting in a contested dismissal of all claims. This patent case involved genotyping technology.

Trial and appellate counsel for Best Buy in RealSource, Inc. v. Best Buy Co., et al. involving patent claims asserted in U.S. District Court in Austin, Texas.  The plaintiff alleged Best Buy's gift cards infringed its patent, and sought more than $32 million in damages.  Summary judgment was granted.  The judgment was affirmed by the Federal Circuit on June 23, 2008.

Trial counsel for plaintiff in Manufacturing Administration and Management Systems, Inc. v. Davox Corporation, et al.  involving patent claims tried in the U.S. District Court in Boston.  Patented technology involved software programs interfacing telephone switches and computers.  Case settled during trial after a finding of infringement under the doctrine of equivalents.

Trial and appellate counsel for defendants in Luigino’s, Inc. v. Robert Peterson and IBP Inc.  Plaintiff asserted a variety of claims for unfair competition, misappropriation of trade secrets and breaches of a confidentiality agreement.  Plaintiff sought $500 million and a shut-down of an entire line of food products.  Obtained summary judgment disposing of all claims.  Affirmed at 317 F. 3d 909 (8th Cir. 2003).

Represented Carlson Marketing Group, Inc. in multiple suits involving patents for filtered and non-filtered processing of data on stored value cards and gift cards.  Assisted the company in reaching various licenses to position itself favorably in the market. 

Represented Carlson Companies, Inc. in the certified national class action Lofton v. Bank of America, FIA Card Services, N.A., Carlson Companies, Inc., et al, in the United States District Court for the Northern District of California, San Francisco Division, in which the class representative alleged various unfair and deceptive trade practices. Reached a Court approved national class settlement.   

Carlson Marketing Group, Inc. v. SME Associates, et al.  Trial counsel for the plaintiff in obtaining a TRO shutting down a line of business based upon alleged misappropriation of trade secrets involving an Olympic hospitality business for the 2004 Summer Games in Athens.  Case settled thereafter. 

The Toro Company v. Outboard Marine Corporation:  Represented plaintiff Toro in an action for fraud and breach of warranties involving Toro’s acquisition of The Lawn Boy product line from Outboard Marine.  Obtained confidential settlement for Toro after Mr. McMahon successfully pierced the attorney/client privilege. 

  • Board of Directors, Children's Heartlink
Bar Admissions
  • Minnesota
  • Missouri
  • U.S. Court of Appeals, Fifth Circuit
  • U.S. Court of Appeals, Eighth Circuit
  • U.S. Court of Appeals, Federal Circuit
  • U.S. District Court, Colorado
  • U.S. District Court, Minnesota
  • U.S. District Court, North Dakota
  • U.S. District Court, Western District of Missouri
  • University of Nebraska College of Law, J.D. (1981), Member of the Board of Editors, Nebraska Law Review
  • University of Nebraska at Lincoln, B.S.
Professional Associations
  • American Bar Association (Antitrust Law Section)
  • Hennepin County Bar Association
  • Minnesota Intellectual Property Law Association
  • Minnesota State Bar Association
  • Missouri Bar Association

  • Frequent speaker at Minnesota Institute of Legal Education seminars on Intellectual Property matters
    (November 8, 2013)
Back to Top