John F. Mariani

John Mariani concentrates his practice in commercial litigation and appeals, including class actions, antitrust and trade regulation, product liability, securities litigation, shareholder, partnership, and member disputes, trademark and patent litigation, and internal investigations.


John has been a trial and appellate attorney for 30 years. During that time, has tried and argued cases ranging from national and international mass tort class actions against the largest companies to complex shareholder disputes over control of closely held business entities.


Early in his career, John served as law clerk of the Honorable Ruggero J. Aldisert of the United States Court of Appeals for the Third Circuit. He then practiced for more than decade in New York and Florida with a prominent Wall Street law firm.


John is former chair of the Florida 15th Circuit Judicial Nominating Commission, and of the Federal Magistrate Judge Merit Selection Panel  for the Southern District of Florida. He also serves on the Advisory Committee on Court-Annexed Mediation for the Southern District of Florida, John is a graduate of the University of Notre Dame and the University of Miami Law School where he was an Executive Board Member of the Law Review.



  • University of Miami, J.D.

  • University of Exeter, England

  • University of Notre Dame, A.B.

Bar Admission

  • Florida

  • New York

  • Pennsylvania


  • Martindale-Hubbell Rated A-V Preeminent

  • Professionalism Award, Palm Beach County Bar Association, 2013

  • The Best Lawyers in America, selected for inclusion, Commercial Litigation, 2011

  • The Best Lawyers in America, selected for inclusion, Product Liability Litigation, 2015

  • Florida Super Lawyers, selected for inclusion, Class Actions/Mass Torts 2012, 2013, and 2014, 2015

  • South Florida Legal Guide, Top Lawyers in South Florida, selected for inclusion, 2014, 2015


Court Admissions

  • U.S. Supreme Court

  • U.S. Court of Appeals, Third, Fifth, Eleventh Circuits

  • U.S. District Court for the Southern and Middle Districts of Florida

  • U.S. District Court for the Southern and Eastern Districts of New York

  • U.S. District Court for the Eastern Districts of Pennsylvania

  • U.S. District Court for New Jersey

  • U.S. Tax Court



  • Understanding Fiduciary Duty,” Florida Bar Journal (March 2010) LINK

  • “Arguing Preemption in the 11th Circuit Post-Levine,” Product Liability Law 360 (Sept 15, 2009)

  • “Educating Employees About Litigation Holds,” Counsel to Counsel (January 2008)

  • “Weighing the Pros and Cons: Dispute Resolution Methods,” Counsel to Counsel (July 2007)

  •  “Handling E-Communications: Explain. Train. Repeat.,” Counsel to Counsel (November 2006)


Civic and Community Service

  • Florida 15th Circuit Judicial Nominating Commission (2008 to 2012)

  • Chair, Federal Magistrate, Judge Merit Selection Panel, Southern District of Florida (2010 and 2011)

  • Advisory Committee on Court Annexed Mediation, United States District Court for the southern District of Florida (2007 to present)



  • Defense Research Institute

  • Securities Industry and Financial Markets Association

  • American Bar Association

  • Federal Bar Association

  • Fellows of the American Bar Foundation

  • The Justice Major B. Harding American Inn of Court

  • The Craig S. Bernard American Inn of Court

  • National Italian American Foundation

  • Monogram Club, University of Notre Dame

  • NIAF - National Italian American Foundation

  • Friends of the Uffizi Gallery

  • Il Circolo


Seminars and Presentations

  • “Emerging Concepts in U.S. Class Actions…, “ American Bar Association, International Law Section (2010)

  • “Product Liability Concerns for International Manufacturers,“ Italian Trade Commission (2008)

  • “Lawyering in the International Market – Trademark Litigation in the United States,” Center for International Legal Studies (2005)

  • “Defeating Class Certification in Consumer Class Actions,” Palm Beach County Bar Assoc., Commerical Litigation CLE Committee (2005)

  • “Obtaining Personal Jurisdiction,” Florida Bar, International Litigation & Arbitration Committee (2004)


Reported Opinions

  • Amegy Bank National Ass’n v. Deutsche Bank Alex Brown,  Case No. 14-12568 (11th Cir.,  Aug. 15, 2015);

  • Rosenberg v. DVI Receivables, XIV, LLC, et al., Case No. 12-22275-CIV-SEITZ (S.D. Fla., Sept. 29, 2014)

  • Buckley Towers Condominium, Inc., et al., v. Katzmann Garfinkel Rosenbaum, LLP,  Case No. 12-12039 (11th Cir., May 20, 2013)

  • Pop’s Pancakes, Inc. v. NuCO2, Inc., 251 F.R.D. 677 (S.D. Fla.), appeal dismissed, No. 01-01079EE (11th Cir.)

  • Palm Beach Shores v. City of Riviera Beach, 916 So.2d 25 (Fla. 4th DCA)

  • Timko v. Triarsi, 898 So. 2d89 (Fla. 5th DCA)

  • Argus Photonics Group, Inc. v. Dickenson, 841 So.2d 598 (Fla. 4th DCA)

  • Blackpool Associates, Ltd. v. SM-106, Ltd., 839 So.2d 837 (Fla. 4th DCA)

  • Choice Restaurant Acquisition Ltd. v. Whitley, Inc., 816 So.2d 1165 (Fla. 4th DCA)

  • Unico Holdings, Inc. v. Nutramax Products, Inc., 264 B.R. 779 (S.D. Fla.)

  • Abbott Laboratories v. Unlimited Beverages, Inc., 218 F.3d 1238 (11th Cir.)

  • Coastal Fuels Marketing, Inc. v. Florida Exp. Shipping Co., Inc., 207 F.3d 1247 (11th Cir.)

  • Americare Biologicals, Inc. v. Technical Chemicals & Products, Inc., 766 So.2d 284 (Fla. 4th DCA)

  • Milbar Medical Co., Inc. v. Medicis Pharmaceutical Corp., 741 So.2d 1198 (Fla. 4th DCA)

  • Alevizos v. John D. and Catherine T. MacArthur Foundation, 764 So.2d 8 (Fla. 4th DCA)

  • Boca Airport, Inc. v. Roll-N-Roaster of Boca, Inc., 690 So.2d 640 (Fla. 4th DCA)

  • Baber v. Wonderland Greyhound Park, 656 So.2d 961 (Fla. 5th DCA)

  • Kelly v. Kelly, 911 F. Supp. 518 (M.D. Fla.)

  • Kelly v. Kelly, 901 F. Supp. 1567 (M.D. Fla.)

  • Gemeinschaft Europaischer Kunstler Anastalt v. Miami Freedom Tower, Inc., 625 So.2d 83 (Fla. 3d DCA)

  • Belcher Oil Co. v. Florida Fuels, Inc., 749 F. Supp. 1104 (S.D. Fla.)

  • In re “Agent Orange” Product Liability Litigation MDL No. 381, 818 F.2d 145 (2d Cir.), cert. denied sub nom, Pinkney v. Dow Chemical Co., 484 U.S. 1004

  • In re “Agent Orange” Product Liability Litigation, 597 F. Supp. 740 (E.D.N.Y.)

  • United States v. Bedford Associates, 713 F.2d 895 (2d Cir.)