Practice Areas

Litigation  •   White Collar Defense & Investigations  •  

Jeffrey P. Mongiello is Counsel in the CSG Law Litigation Group.

Jeff focuses his practice on white collar criminal matters, government investigations and internal corporate investigations, commercial disputes, and appellate litigation, often serving clients in highly regulated industries. As a former prosecutor, he helps clients navigate and resolve investigations inquiries, litigation, and charges.

Prior to joining the firm, Jeff served as an associate at a national law firm and a regional law firm, and as a judicial law clerk for both the Honorable Mary L. Cooper, U.S. District Court for the District of New Jersey, and the Honorable Anne M. Patterson, New Jersey Supreme Court.

Before entering private practice, Jeff served as a New Jersey State Deputy Attorney General in the Appellate Bureau of the Division of Criminal Justice, where he represented the State before the Appellate Division and New Jersey Supreme Court. In this role, he successfully defended against a constitutional challenge before the New Jersey Supreme Court to the state’s judicial recall statute, which authorizes retired judges over the age of 70 to temporarily return to service.

Jeff was recognized in 2015 with the Attorney General’s Award for Excellence in Trial Litigation for his role in a successful public corruption prosecution by twice securing reversals on interlocutory appeals of the trial court’s rulings.

Jeff earned his J.D., magna cum laude, from Seton Hall University School of Law, where he was Managing Editor of Seton Hall Law Review, his Master’s in Public Policy from the University of Maryland School of Public Policy, and his B.A. from the University of Maryland.


  • Included in New Jersey Law Journal, New Leaders of the Bar (2021)
  • Included in The Best Lawyers in America® “Ones to Watch,” Criminal Defense: White Collar (2022-2023); Commercial Litigation (2021-2023)
  • Selected to the New Jersey Super Lawyers – Rising Stars list, Criminal Defense: White Collar; Appellate; Civil Litigation: Defense; Class Action/Mass Torts: Defense (2022-2023)
  • Recipient, New Jersey Attorney General’s Award for Excellence in Trial Litigation (2015)

Award Methodology
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  • New Jersey State Bar Association, Appellate Practice Committee; Criminal Law Section
  • National Association of Criminal Defense Lawyers
  • Association of Criminal Defense Lawyers of New Jersey
  • New Jersey Ethics Committee, District VI (Hudson County)


  • Seton Hall University School of Law (J.D., magna cum laude, 2011)
  • University of Maryland School of Public Policy (M.P.P., 2006)
  • University of Maryland (B.A., 2005)


  • New Jersey
  • New York
  • U.S. Court of Appeals, Third Circuit
  • U.S. Court of Appeals, Fifth Circuit
  • U.S. District Court, District of New Jersey
  • U.S. District Court, Eastern District of New York
  • U.S. District Court, Southern District of New York