Daniel R. Sonneborn is a director in the firm's Litigation Group, practicing primarily from the firm’s Boston office. His practice areas include professional liability, construction, financial services and commercial litigation. Dan regularly represents medical professionals, attorneys, accountants, small and large businesses, and insurance companies in state and federal courts in Massachusetts, Maine and New Hampshire.  

Dan's practice also focuses on transportation law, representing motor carriers, brokers, freight forwarders, and insurance companies in transportation related matters and litigation, including cargo loss and damage, warehousing, contractual issues, and employment matters.

While at Suffolk University School of Law, Dan served as Managing Editor of the Journal of Health and Biomedical Law. He lives in Medford, Massachusetts with his wife and two children.

Practice Areas


  • Bowdoin College (A.B., 2007)
    • Member, Men's Ice Hockey Team
  • Suffolk University Law School (J.D., 2010)


  • Massachusetts
  • Maine
  • New Hampshire
  • U.S. District Court, District of Massachusetts
  • U.S. District Court, District of Maine
  • U.S. District Court, District of New Hampshire
  • U.S. Court of Appeals, First Circuit

Professional Affiliations

  • Maine State Bar Association
  • New Hampshire State Bar Association
  • Defense Research Institute

Civic Involvement

  • Pan-Mass Challenge

Representative Matters

  • Received a defense verdict on behalf of physician following a two-week trial alleging wrongful death due to failure to diagnose a cervical fracture and epidural hematoma.
  • Represented large multinational corporation in dispute with general contractor over completion of $4 million dollar complex which resulted in conclusion of project without the need for court intervention


  • Co-author, Introduction, A Practical Guide to Understanding RSA 358-A in New Hampshire (MCLE New England, 1st Edition, 2014).