Nathaniel R.B. Koslof

Nathaniel R.B. Koslof


Nate is a trial lawyer with experience in a wide range of complex commercial litigation matters, including the representation of parties in contract, tort, real estate, trust and insolvency-related disputes in state and federal court. His background in business litigation and bankruptcy law enables him to provide clients with strategic advice and to resolve commercial disputes efficiently and in the client's best interest.

Nate has significant trial experience in both state and federal court, including as first chair and second chair in trials in Massachusetts and New Hampshire courts. Nate has successfully argued motions to dismiss and motions for summary judgment in state and federal courts. Through his partnership with the Victim Rights Law Center, Nate regularly represents victims of domestic violence and has helped them obtain several 209A restraining orders / 258E harassment prevention orders, including a lifetime order. Nate has also argued before the United States Court of Appeals for the Second Circuit.

Prior to joining Donnelly, Conroy & Gelhaar, Nate was a senior litigation associate at Sullivan & Worcester LLP in Boston, where in addition to his broad litigation practice, Nate prosecuted and defended hundreds of Bankruptcy Court adversary proceedings concerning preferential transfers and fraudulent conveyances, successfully resolving these matters through mediation or otherwise.

Nate has been honored as a Massachusetts Super Lawyer “Rising Star” (2022) and as “One to Watch” by Best Lawyers in America® (2021-2023). Nate was also a recipient of the 2021 Pro Bono Honor Roll by the U.S. Bankruptcy Court for the District of Massachusetts.


Trial Experience

  • Served as lead counsel in Bankruptcy Court trial; obtained an exception to discharge under Section 523(a)(6) of the Bankruptcy Code.
  • Represented defendant in a multi-plaintiff, two-week trial in New Hampshire state court; obtained determination that public did not acquire prescriptive easement rights over client’s property.
  • Represented borrower in multi-defendant, three-week bench trial in Massachusetts state court concerning allegations of usurious lending, wrongful foreclosure and other unfair and deceptive actions in violation of Chapter 93A.
  • Represented defendant in a trial in the Boston Municipal Court concerning allegations of reckless/negligent operation of a motor vehicle; obtained acquittal on all counts.

Commercial Litigation / Real Estate Litigation / Bankruptcy Litigation

  • Obtained summary judgment for commercial landlord in breach of contract case in Massachusetts Superior Court; enforced liquidated damages provision and obtained award of attorneys’ fees and costs.
  • Obtained summary judgment for private investment company in a multi-million dollar contract dispute in the United States District Court for the Southern District of New York.
  • Represented a global real estate company in a contract dispute concerning the company’s purchase of a >$50 million property; obtained favorable resolution following motion for summary judgment.
  • Represented residents of a coastal Massachusetts town in a dispute over the scope of public easements across their property.
  • Represented property owner before Appellate Tax Board; obtained significant tax abatement.
  • Represented professional athlete in an action in the Southern District of California against former trainer involving claims of breach of contract, breach of fiduciary duty and failure to obtain informed consent; obtained favorable resolution following mediation.
  • Represented NFL player in his charge of unfair labor practices before the National Labor Relations Board against the NFLPA and his former team.
  • Prosecuted hundreds of adversary proceedings concerning preferential transfers and/or fraudulent conveyances; successfully resolved these matters through mediation or otherwise.

Pro Bono

  • Argued before United States Court of Appeals for the Second Circuit on appeal of the District Court’s denial of client’s habeas petition pursuant to 28 U.S.C. § 2255.
  • Represented dozens of victims of domestic violence in 209A/258E restraining order proceedings; obtained multi-year restraining order extensions, including a lifetime order.
  • Represented individuals in administrative hearings before the Massachusetts Department of Unemployment Assistance and judicial review proceedings in the Boston Municipal Court; overturned denial of unemployment benefits; obtained waiver of overpayment demands.
  • Represented parent in child abduction and Hague Convention case in federal court.



  • JD, Cum laude, Boston College Law School
  • BA, Washington University in St. Louis


  • Commonwealth of Massachusetts
  • United States District Court, District of Massachusetts
  • United States Court of Appeals for the First Circuit; United States Court of Appeals for the Second Circuit