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Sean Mack


Sean Mack


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Prior to joining PSWH, I worked at one of the top international law firms in Manhattan and enjoyed the cutting edge work, and spirit of collegiality at that firm. I joined Pashman Stein because I wanted to continue to work on cutting edge, bet the business matters, but in a smaller platform where I could be an integral part of building a different type of law firm. The last 14 years have been an incredible journey growing the firm from 10 attorneys to 56 across 3 offices by recruiting top lateral talent, while demonstrating that you can build a small firm that competes with, or collaborates with, the biggest firms in the country for top work, while maintaining a family-friendly work environment and a real commitment to team work and collaboration.


Sean Mack is the co-chair of the Firm’s Litigation practice. Sean’s practice focuses on complex disputes involving unfair business competition in a variety of forms. Sean regularly represents businesses, business owners and senior executives in lawsuits involving theft of corporate opportunities, theft of trade secrets, breaches of non-competition agreements, breaches of confidentiality and non-disclosure agreements, and other unfair business practices. Clients often retain Sean when a joint business venture has gone awry or when they believe it is time to divorce their business partners.  Many of his cases arise from complicated contractual and licensing disputes. He also has represented clients in trademark and trade dress infringement cases and in counterfeiting cases.

Sean is an experienced appellate advocate, having presented appeals in several federal appellate courts and New Jersey’s Appellate Division. He provides advice to Firm clients on bankruptcy and insolvency-related issues and represents creditors in bankruptcy proceedings.  He also has represented several Firm clients in contested probate proceedings.

Sean represents motor carriers in contract disputes and has provided advice on a variety of legal issues affecting motor carriers and the intermodal shipping industry.

Sean also is leading the development of the Firm’s Cannabis and Hemp Practice. Beginning in 2015, Sean led a team of the Firm’s attorneys to analyze existing cannabis laws and regulations to prepare proposed legislation for New Jersey United for Marijuana Reform. NJUMR then presented the Firm’s proposal to a state senator for incorporation into an early draft of the bill to legalize adult use marijuana in New Jersey. Building on that experience, he currently advises ancillary service providers to the cannabis industry and businesses interested in applying for cannabis licenses.

Reported Decisions

  • National Lighting Company, Inc. v. Bridge Metal Industries, LLC, 601 F.Supp.2d 556 (S.D.N.Y. 2009)
  • Strahan v. Strahan, 402 N.J.Super. 298 (App. Div. 2008)
  • Arnold v. Arnold, 2007 WL 1146627 (N.J. App. Div. 2007)
  • In re XO COMMUNICATIONS, INC., 323 B.R. 330 (Bankr. S.D.N.Y. 2005)
  • Hawa Abdi Jama v. Esmor, 343 F.Supp.2d 338 (D.N.J. 2004) and 334 F. Supp 2d 662 (D.N.J. 2004)
  • Burns v. Anderson, 123 Fed.Appx. 543 (4th Cir. 2004)
  • In re RSL Primecall, Inc., 2003 WL 22989669 (Bankr. S.D.N.Y. 2003)

Representative Matters

  • Successfully obtained the dismissal of all federal Lanham Act claims brought by a lighting company against its former contract manufacturer in a suit alleging that the manufacturer stole trade secrets and was improperly competing with the lighting company in breach of a confidentiality agreement. Then successfully obtained the dismissal of a follow-on lawsuit in state court on the basis of choice of law and personal jurisdiction defects. We then successfully pursued insurance coverage for all of the defense costs and expenses in federal court and on appeal before the Second Circuit Court of Appeals.
  • Represented, a leading heart valve manufacturer in a patent licensing dispute involving rights to a minimally invasive method for repairing and replacing aortic heart valves (transcatheter aortic valve replacement therapy). The dispute focused on whether only a particular patent or an entire family of patents to the revolutionary heart valve device and procedure had been licensed. Following an evidentiary hearing on our application for summary judgment, the matter was resolved through a confidential settlement.
  • Successfully obtained a preliminary injunction prohibiting a former senior executive from competing against his former employer anywhere in the state of New Jersey and successfully prosecuted an order for sanctions when the former employee violated the injunction.
  • Successfully defended a lawsuit brought by a sibling in a family owned business, who after 30 years of having no involvement with the business, demanded his share of the business and its profits. Despite the existence of an old stock ledger supporting the claim, the plaintiff was awarded zero dollars on his claims.

Professional/Civic Activities

  • Member, New Jersey Bar Association
  • Member, Bergen County Bar Association
  • Former Member, District II-B Ethics Committee


  • “Restrictive Covenants in New York and New Jersey,” Lawline.com, March 2012,
  • “Safeguarding Your Assets: Can You Protect Opportunities,” Financial Management Network, November 2011

Bar/Court Admissions

  • New Jersey
  • New York
  • United States District Court, District of New Jersey
  • United States District Court, Southern District of New York
  • United States District Court, Eastern District of New York
  • United States District Court, Northern District of New York
  • United States Court of Appeals, Second Circuit
  • United States Court of Appeals, Fourth Circuit
  • United States Court of Appeals, Sixth Circuit


  • B.A., College of the Holy Cross, cum laude, 1995
  • J.D., Rutgers University School of Law, with highest honors, Order of the Coif, 1999

Honors and Accolades

  • InsiderNJ, “Insider 100 Cannabis Power” List, 2019
  • Best Lawyers, Commercial Litigation, 2013-2020
  • New Jersey Law Journal, “40 Under 40”, 2009, 2011
  • New Jersey Super Lawyers, Rising Star, 2010-2013
  • New Jersey Super Lawyers, 2016-2019

The Super Lawyers list is issued by Thomson Reuters. A description of the selection methodology can be found at http://www.superlawyers.com/about/selection_process.html.

The Rising Stars list is issued by Thomson Reuters. A description of the selection methodology can be found at http://www.superlawyers.com/about/selection_process.html.

New Jersey Law Journal’s list is issued by the New Jersey Law Journal. A description of the selection methodology can be found at http://www.njlawjournal.com/id=1202432890579/40-Under-40

The Best Lawyers list is issued by Woodward/White, Inc. A description of the selection methodology can be found at https://www.bestlawyers.com/About/MethodologyBasic.aspx.

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Practice Areas