Seth Rosenstein-600

Seth M. Rosenstein


Seth Rosenstein is an attorney in the Litigation, Controlled Substances and Regulatory Law and Residential Real Estate departments. He has significant experience representing clients in the negotiation and litigation of commercial and civil disputes in state and federal courts, as well as before American Arbitration Association and Financial Industry Regulatory Authority arbitration panels. Seth has practiced in all aspects of securities class action litigation before state and federal courts throughout the United States and serves as a FINRA Dispute Resolution Services Arbitrator. He also regularly handles residential real estate transactions in New Jersey and New York.

Seth represents a wide range of clients, from large commercial property owners to individuals, across a broad spectrum of industries, including real estate, financial services, construction, cannabis, manufacturing, trucking and more in connection with contract disputes, torts, regulatory issues, construction and real estate issues, shareholder disputes, and various other business-related disputes. He has developed a particular expertise prosecuting and defending alleged violations of consumer protection and related statutes. While recognized as an aggressive and focused litigator, Seth’s focus is on positioning each action to achieve each client’s desired outcome in the most efficient manner.

Immediately prior to joining Ansell Grimm & Aaron, Seth practiced in the Manhattan office of a national litigation firm. Prior to bar admission, he served as an intern with the New York State Department of Financial Services, the Kings County District Attorney’s Office and the Federal Deposit Insurance Corporation.

Representative Matters

  • Secured dismissal at the pleading stage of claims in an investor dispute, including an award of costs and disbursements
  • Successfully defended a wholesale insurance broker on breach of contract and negligence claims
  • Obtained temporary restraints on behalf of a corporate client in a dispute involving a hemp cultivation and harvesting facility
  • Represented a Fortune 500 financial services company in arbitration actions brought before FINRA arbitration panels
  • Contributed to a successful appeal securing stay of all administrative proceedings relating to applications for marijuana alternative treatment centers in New Jersey following disqualification of certain applicants
  • Defended construction and design defect claims brought by a large cooperative building complex in New York City against an engineering firm
  • Successfully vacated an eight-year-old default judgment awarded to a state administrative agency, reversed seizure of funds and combatted litigation abuses undertaken by state’s outside counsel
  • Obtained a pre-discovery summary judgment dismissal of an action against a commercial landlord and city marshal alleging unlawful eviction, wrongful seizure of property and intentional infliction of emotional distress
  • Successfully opposed a county government motion to compel a third party to provide defense in a breach of contract dispute


  • New Jersey Bar
  • New York Bar
  • Pennsylvania Bar
  • United States District Court for the District of New Jersey
  • United States District Court for the Southern District of New York
  • United States District Court for the Eastern District of New York
  • United States District Court for the Eastern District of Pennsylvania
  • United States Court of Appeals for the Second Circuit
  • United States Court of Appeals for the Third Circuit

Associations & Memberships

  • Bergen County Bar Association
  • Westchester County Bar Association


New York, NY
Woodland Park, NJ

Support Staff

Assistant: Lymari Ramos

Practice Areas


Benjamin N. Cardozo School of Law, Yeshiva University, J.D., 2015

American University, B.A., 2011