Sean M. Koller - McDermott Will & Emery


Sean M. Koller represents clients involved in complex business litigation, including healthcare disputes, bankruptcy and adversary proceedings, derivative suits, employment disputes, and contractual claims. Sean represents clients in litigation pending in federal and state courts throughout the country, and has handled matters before the American Arbitration Association, JAMS, and other alternative dispute resolution tribunals.

Sean also defends individuals and corporations against governmental investigations by the Department of Justice, Securities and Exchange Commission, Public Company Accounting Oversight Board, State Attorneys General, and other state and federal government agencies.  He has experience conducting internal investigations of public corporations and non-profit organizations.


  • Obtained complete acquittal after eight-day criminal jury trial in first ever criminal no poach trial in the 130+ year history of the Sherman Act on behalf of Kent Thiry, former CEO of DaVita, Inc.
  • Served as trial counsel for the defendant, the leading maker of office headsets, in an antitrust action between direct competitors; McDermott was brought in to try the case shortly before trial and, despite an adverse inference instruction on spoliation that was ordered prior to the Firm’s involvement, the jury returned a complete defense verdict (District of Delaware).
  • Defended a broad spectrum of organizations, including healthcare providers and systems, accounting firms, and publicly traded companies, in connection with government investigations and related litigation.
  • Represented the officers and directors of nationally recognized utility in derivative and class action litigation arising from large-scale wildfires.
  • Conducted a pro bono internal investigation of misappropriation by an employee of a nonprofit agency.
  • Represented, on a pro bono basis, an individual in a post-conviction petition claiming actual innocence of the defendant based on new evidence.


University of Notre Dame, BA, History, magna cum laude, 2013
University of Chicago Law School, JD, 2016