Michael J. Sullivan

Michael J. Sullivan


Michael J. Sullivan is an Associate in the Sills Cummis & Gross Litigation Practice Group. His practice focuses on complex commercial litigation and white collar and securities litigation matters. He represents corporate and individual clients in commercial matters involving allegations of fraud, breach of contract, breach of fiduciary duty and similar claims of wrongdoing. He also has advised clients in federal and state criminal and regulatory investigations, enforcement proceedings and internal investigations.

Mr. Sullivan has represented clients in trials in both state and federal courts, as well as in mediations. 

Prior to joining the Firm, Mr. Sullivan was an associate at Dechert in New York.  

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Representative Matters

  • Represented an international auto parts manufacturer in connection with investigations of alleged defects by the National Highway Traffic Safety Administration, Congress, the Department of Justice and other government entities, and in related civil litigation.
  • Represented a private equity firm in related lawsuits brought in New York state court alleging breach of contract, fraud, breach of fiduciary duty, and other claims arising out of disputes over the management of residential properties in Pennsylvania and Indiana.
  • Represented a bond trader in an SEC investigation regarding alleged misrepresentations and market manipulation.
  • Successfully defended an international express mail delivery company in a month-long jury trial in New York state court against multi-million dollar breach of contract claims brought by 31 businesses. Has also represented this client at the trial and appellate level in several matters pending in state and federal courts involving breach of contract and business tort claims.
  • Successfully defended a Mexican entertainment company in a bench trial in federal court on breach of contract claims by affiliates of an international movie theatre chain arising out of the purchase of a group of Mexican cinemas.
  • Represented a lawyer at a mutual fund in an SEC investigation regarding alleged conflict of interest violations.
  • Successfully earned dismissal of breach of contract and business tort claims against a multinational bank in litigation brought by a Spanish energy company arising out of Argentina’s expropriation of the energy company’s ownership in an Argentine oil company. 

Court Admissions

U.S. District Court, District of New Jersey, 2010
U.S. District Court, Southern District of New York, 2011
U.S. District Court, Eastern District of New York, 2011


Member, New York State Bar Association
–    Member, Committee on Cannabis Law