Matt Reilly is a partner in the Washington, D.C., office of Kirkland & Ellis LLP. Matt is one of the preeminent antitrust practitioners in the country. Matt’s practice focuses on a wide range of antitrust matters, including antitrust litigation, complex transactions and antitrust counseling and government investigations. He is regularly relied on by major clients to navigate the approval process for the most complex, high-profile transactions, and to prepare to litigate mergers that face steep resistance from the agencies.

Matt has led over a dozen agency-litigated merger challenges, representing either the FTC or the merging parties. During his many years in senior roles at the FTC, Matt led many of the agency’s most prominent merger matters and, as a result of his litigation achievements, received the Commission’s highest recognition, the Chairman’s Award. More recently, in the last ten years alone, Matt has been brought into more than ten merger investigations post-Second Request to supplement existing counsel to obtain deal approval after the FTC or DOJ has signaled serious concerns, to prepare for litigation, and, if necessary, to litigate the deal on behalf of the merging parties. Matt is one of a very small number of active antitrust attorneys to have led as first-chair trial counsel successful merger trials both for and against the federal enforcement agencies. As a result of his career accomplishments, Matt was recently elected into the five-member inaugural class of Legal 500’s Antitrust Merger Control Hall of Fame as one of its youngest members. One prominent client describes Matt simply as “the fixer — their first and clear choice for a deal that is facing a really tough fight” at the agency or in litigation.

Matt also frequently assists clients navigating non-merger litigations and investigations. His experience includes securing unconditional closure of multiple FTC and DOJ Sherman Act investigations, and his clients in this area include several Fortune 100 technology and health care companies. Matt was recently retained by two Fortune 20 companies to take a leading role in high-stakes agency conduct investigations.


Thought Leadership


“Merger Remedy Divestitures: the Agencies Zig and the Courts Zag,” Antitrust (September 16, 2023) – Winner, 2024 Antitrust Writing Awards: Business Articles, Mergers (Concurrences)

Speaking Engagements

Guest Speaker on UHG/Change and merger litigation at the Kellogg School of Business, University of Chicago

Speaker at ABA-sponsored panels, New York Bar Association conferences and economic symposiums


Recognized as “Hall of Fame” for Antitrust: Merger Control by The Legal 500, 2020-2023

Recognized for Antitrust in the District of Columbia by Chambers USA, 2014-2023

Recognized for Antitrust Law by Best Lawyers®, 2021–2024

Recognized as a Global Leader (2022) and a Thought Leader (2023) by Who’s Who Legal

Recognized as “Outstanding” in Washington, D.C., by Global Competition Review 100, 2022

Recognized as Litigator of the Week for UnitedHealth Group/Change win against DOJ


Admissions & Qualifications

  • District of Columbia
  • Massachusetts


  • Supreme Court of the United States
  • United States Court of Appeals for the Fourth Circuit


  • Georgetown University Law CenterJ.D.cum laude1995
  • Duke University Sanford School of Public PolicyM.A.1991

    First in class

  • Colby CollegeB.A.magna cum laude1988

    Phi Beta Kappa