Cozen O’Connor: Eisenstark, Gregory

Gregory Eisenstark



(973) 200-7411

Greg maintains a comprehensive energy and utility regulatory practice, with experience in base rate cases, rate clause filings, reliability issues, public utility project siting applications and appeals, utility industry mergers and acquisitions, renewable energy, including solar and offshore wind projects, demand response and energy efficiency issues, regulatory audits, provider of last resort and third-party supplier issues, utility financing issues, formula rate cases, and transmission incentive rate filings. He has experience in administrative rulemaking, drafting legislation, and counseling on energy policy issues, as well as appellate experience in both state and federal courts. 

Greg has litigated hundreds of utility rate and regulatory filings to successful completion. Since the early 1990s, he has handled many base rate cases involving water, wastewater, natural gas and electric utilities. Currently, Greg is lead counsel for New Jersey Natural Gas Company in its base rate case.

Prior to private practice, Greg served as associate general regulatory counsel for Public Service Enterprise Group (PSEG), where he represented PSEG's operating companies in regulatory matters before the New Jersey Board of Public Utilities, the Federal Energy Regulatory Commission, other state utility commissions, and in state and federal courts. Earlier in his career, Greg was managing attorney – electric for the New Jersey Division of Ratepayer Advocate, where he represented utility customers in matters before regulatory agencies and courts. In that capacity, Greg played an active role in the transformation of the PJM Interconnection from a power pool to an independent system operator. Before that, Greg was a deputy attorney general of New Jersey, where he represented the Board of Public Utilities and Department of Environmental Protection in utility and solid waste industry matters.

Greg earned his bachelor’s degree from Oberlin College. Greg earned his law degree from Rutgers University School of Law - Newark.



Cozen O’Connor Announces Hiring Two Nationally Renowned Energy Lawyers and Continues Expansion of its U.S. Footprint, Opening a Newark, N.J. Office

April 01, 2019

Gregory Eisenstark and Michael J. Connolly join Cozen O’Connor and will lead the Newark office


  • Rutgers University School of Law—Newark, J.D., 1991
  • Oberlin College, B.A., 1984

Awards & Honors

The Best Lawyers in America, Energy Law, 2016-2019

The Best Lawyers in America, Lawyer of the Year for Energy Law, 2019

  • New Jersey
  • New York
  • Pennsylvania
  • U.S. Court of Appeals for the Third Circuit
  • U.S. Court of Appeals for the District of Columbia Circuit
  • U.S. District Court -- New Jersey

American Bar Association

New Jersey State Bar Association, Public Utility Law Section

New Jersey Utilities Association