John F. Marsh

Partner 614.233.5102


John F. Marsh has experience representing and advising clients in trade secrets, emergency litigation, licensing and intellectual property disputes, injunctive proceedings including temporary restraining orders and preliminary injunction hearings, securities and shareholder disputes, mediations and arbitrations, commercial and contractual disputes, product liability lawsuits and issues, jury trials and evidentiary hearings, and other complex legal matters. John discusses these topics and more on his blog at, on Twitter at @TSLitigator, and on LinkedIn at

At Hahn Loeser  

Representative Matters:
  • Lead counsel for the Bank of New York in extensive injunctive, evidentiary and appellate proceedings that thwarted a white collar fraud ring's attempts to convert $18 million in bank assets; secured contempt orders and various judgments totaling more than $750,000 in attorneys' fees and costs.
  • Lead counsel for securities affiliate of a national bank in extensive state court injunctive proceedings and co-counsel for related NASD permanent injunctive proceedings arising out of the departure of a team of financial analysts, sales representatives and other former employees to form a competitor; through that litigation, client was able to secure favorable settlement barring contact with key customers despite absence of noncompetition agreements.
  • Secured preliminary injunction for the national realtor, HER Real Living, and its principals enjoining a competitor from "cyber squatting" and improperly using certain internet domain names.
  • Secured injunction and favorable consent decree on behalf of national computer consulting firm against competitor and former employee to preserve client's trade secrets, enforce that employee's covenant not to compete, and enforce non-solicitation agreement against competitor.
  • Secured injunction on behalf of scholastic manufacturer Herff Jones, Inc. enforcing covenant not to compete against former sales representative and distributor and successfully dissolved ex parte TRO entered against client in related proceeding.
  • Defeated injunction sought against the United States Olympic Committee by Ohio Taekwondo Association that would have effectively displaced USOC from supervising the sport of taekwondo throughout the United States.
  • Secured various orders freezing national telemarketer's assets to prevent dissipation and/or transfer of those assets through bankruptcy.
  • Secured favorable settlement after successful cross-examination and effort to strike testimony of critical expert witness in toxic tort jury trial.
  • Successfully removed shareholder physician from medical practice after two-day preliminary injunction hearing.

Recent Presentations:

  • Presenter, “Trade Secrets vs. Patents: Which Protection is Best for Your IP?” Practising Law Institute Webinar, October 2010.
  • Speaker, “Litigating the Trade Secret and Non-Compete Case in the Present Economy,” Ohio State Bar Association, August 2010.
  • Speaker, "Current Developments in Non-Competes and Non-Disclosure Agreements," Ohio State Bar Association Seminar: Advising Corporate Directors and Officers, May 2010.
  • Speaker, “Trade Secret Protection vs. Patent Protection: Which Protection is Best For Your IP?” Columbus Intellectual Property Law Association Meeting, March 2010.
  • Speaker, "Steps to Take Pre- and Post-Litigation to Protect Trade Secrets," American Intellectual Property Law Association Mid-Winter Meeting, January 2010.

John is listed in the 2009-17 editions of Ohio Super Lawyers, the 2016 edition of The Best Lawyers in America in the category of Litigation - Intellectual Property, and he is AV® Preeminent™ Rated by Martindale-Hubbell, its highest available rating for legal ability and professional ethics.




John Carroll University B.A., cum laude 1986


Vanderbilt University Law School J.D. 1989

Memberships & Affiliations

American Intellectual Property Law Association, Chair, Trade Secret Law Committee


Columbus Bar Association, Member, Federal Court Committee


Common Pleas Court Committee


Securities Committee


Technology and the Law Committee


and Lawyers for Justice


Defense Research Institute, Member, Commercial Litigation and Product Liability Committees


Ohio State Bar Association, Member


U.S. District Court for the Southern District of Ohio, Member



Bar Admissions

State of New York


State of Ohio


U.S. Court of Appeals for the Sixth Circuit


U.S. District Court for the Eastern District of New York


U.S. District Court for the Northern District of Ohio


U.S. District Court for the Southern District of New York


U.S. District Court for the Southern District of Ohio