Former US Attorney and Homeland Security Advisor Ken Wainstein joins Mayer Brown

Washington DC, April 1, 2025 – Mayer Brown announced today that Ken Wainstein has joined the firm in Washington DC as leader of its Global Investigations & White-Collar Defense practice and member of its National Security and Congressional Investigations practices. Ken has served in senior roles across both Republican and Democratic administrations, including US Attorney for the District of Columbia, Assistant Attorney General for National Security, Assistant to the President and Homeland Security Advisor, and most recently Under Secretary for Intelligence and Analysis at the Department of Homeland Security. Prior to his recent government service, Ken worked in private practice for more than 13 years.

"Having known Ken personally and professionally for well over a decade, I am confident that his leadership and depth of experience in both the public and private sectors will enhance our market-leading Global Investigations & White-Collar Defense and National Security practices,” said Raj De, member of the firm’s global Management Committee and leader of the global Cybersecurity & Data Privacy and National Security practices at Mayer Brown. “His expertise will bolster our ability to provide top-tier strategic yet practical counsel to clients facing high-stakes investigations, regulatory scrutiny, congressional investigations, and complex litigation, particularly in the current dynamic enforcement environment." 

At Mayer Brown, Ken’s practice will focus on assisting clients with their most significant criminal and civil enforcement proceedings, corporate internal investigations, and congressional inquiries. Ken’s experience spans the full spectrum from complex white-collar matters to those involving export controls, sanctions, foreign direct investment, and other national security enforcement issues. Having previously led numerous high-profile independent investigations and sensitive internal reviews for corporate boards, Ken’s practice will also include internal investigations and compliance work, and the counseling and representation of clients who are facing significant legal and regulatory challenges. In addition to his new role at Mayer Brown, Ken recently rejoined the Bipartisan Commission on Biodefense as a Commissioner.

"I have always admired Mayer Brown as an exceptional firm with tremendously skilled practitioners and a well-deserved reputation for strong and innovative work in my practice areas of white-collar defense and investigations, national security, and congressional representations,” said Ken. “That reputation is built on the firm’s long tradition of legal excellence along with a strong culture of collaborative client service and a depth of white-collar and national security legal talent that is second to none. The result is a firm that is uniquely well-positioned to meet the needs of its clients in the current legal environment, and a firm that I’m honored to call my professional home." 

Ken spent 23 years in a variety of senior law enforcement and national security positions in the federal government. In addition to his White House service and three Senate-confirmed positions, Ken served as Director of the Executive Office for US Attorneys and as General Counsel and then Chief of Staff of the FBI. Ken also served for over a dozen years as an Assistant United States Attorney prosecuting and supervising criminal cases in the Southern District of New York and the District of Columbia.

"Ken's deep expertise, combined with his extensive background both in public service and private practice, is a perfect complement to our growth strategy,” added Mayer Brown Chair Jon Van Gorp. “His addition underscores our commitment to expanding our versatile, full-service white-collar practice by investing in top talent tailored to meet the evolving demands of our clients and the dynamic nature of today's legal environment." 

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