Stephen Kastenberg > Ballard Spahr LLP > Philadelphia, United States > Lawyer Profile

Ballard Spahr LLP
United States

Work Department





Stephen J. Kastenberg focuses on complex business litigation with an emphasis on antitrust and competition, securities, and corporate governance litigation. He has successfully defended public and private companies and universities in federal and state lawsuits, including class actions, throughout the United States. He also regularly represents clients as plaintiffs in business disputes, or assists them through internal investigations. Stephen is based in Philadelphia and is a member of the firm’s Elected and Expanded Boards.

In his nearly 30 years of litigation experience, Stephen has achieved a significant number of victories through trial, arbitration, summary judgment, advantageous settlement, and on appeal. His clients range from Fortune 100 multinational corporations to privately held companies and nonprofit organizations, and span such industry sectors as pharmaceuticals, chemicals, investments, media and technology, real estate, financial services, and higher education.


New Jersey


Supreme Court of New Jersey

Supreme Court of Pennsylvania

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

U.S. Court of Appeals for the Second Circuit

U.S. Court of Appeals for the Third Circuit

U.S. Court of Appeals for the Fourth Circuit

U.S. Court of Appeals for the Ninth Circuit

U.S. Court of Appeals for the Tenth Circuit

U.S. Court of Appeals for the Eleventh Circuit


American Bar Association, Antitrust Section

New Jersey State Bar Association

Pennsylvania Bar Association

Philadelphia Bar Association

Ballard Spahr’s Pro Bono Committee

New Jersey Scholars Program, Member and past President

Lawyers’ Committee for Civil Rights, Director and Trustee

Police Corruption Task Force, past appointee by Philadelphia Mayor Edward Rendell


Harvard Law School (J.D., cum laude, 1992)
Managing Editor, Harvard Journal on Legislation

Princeton University (A.B., cum laude, 1988)

Lawyer Rankings

United States > Antitrust > Civil litigation/class actions: defense

Monopolization and conspiracy cases form the core of Ballard Spahr LLP‘s antitrust group, which represents clients on both side of the aisle. Leslie John, who has a particular focus on the pharmaceutical and health care industries, leads the practice from Philadelphia, where Jason Leckerman and Stephen Kastenberg are further key members of the team. In New York, James Mitchell is specialized in the securities industry, while Philadelphia-based Edward Rogers handles cases relating to monopolization and conspiracy claims. Denise Plunkett  left the firm in January 2021.