Sean co-chairs the firm’s Regulatory and Administrative Law Practice Group, and his practice divides between antitrust and advising companies in heavily regulated industries. In addition to his years in private practice at Am Law 100 firms, he has served at the U.S. Department of Justice, in both the Antitrust Division and the Office of Legal Counsel.

As a trial attorney in the Antitrust Division’s Civil Conduct Task Force, Sean investigated and litigated civil violations of the federal antitrust laws, with roles in matters including United States v. Apple and United States v. Cargill. In private practice, he has represented clients in competition matters before federal and state courts, the Federal Trade Commission, and the European Commission's Directorate-General for Competition. He also counsels companies on the antitrust review of mergers and acquisitions, including Hart-Scott-Rodino filings and second requests.

Sean’s administrative and constitutional law work grows out of his government service. As an Attorney-Adviser in the Office of Legal Counsel, he provided controlling legal advice to the President and executive branch agencies on novel and difficult questions of constitutional and administrative law, and reviewed executive orders, proclamations, and agency rules for form and legality. He draws on that experience to petition agencies and challenge regulations.

Sean works with clients in sectors such as technology, telecommunications, financial services, energy, life sciences, and agriculture. He helps them stay ahead of new regulatory requirements and changing enforcement priorities. That work extends to consumer protection, where he counsels clients on compliance with the Federal Trade Commission Act, including advertising and disclosure requirements, and on responding to agency investigations and consent orders.

Earlier in his career, Sean clerked for Judge David Sentelle of the U.S. Court of Appeals for the D.C. Circuit and for Chief Judge Royce C. Lamberth of the U.S. District Court for the District of Columbia.

Sean attended New York University School of Law as an AnBryce Scholar, a full-tuition program for students who are among the first in their family to pursue a professional degree and who have demonstrated leadership in the face of social and economic adversity. He later served the AnBryce Foundation as Chair of its Advisory Council and as a Trustee.