Mark E. Warren

Mark E. Warren



Worked on every major tax-policy debate since the Clinton administration. Senior leadership experience in both chambers of Congress and at the Treasury Department.

Mark Warren is a well-respected professional on the Hill, having spent more than two decades serving as congressional tax counsel spanning four administrations. Most recently, Mark served as chief tax counsel to the Senate Finance Committee, where he was responsible for the development and implementation of Chairman Chuck Grassley’s (R-IA) tax agenda, including advising on all aspects of federal tax, retirement, pensions and tax-administration policy. He also managed the committee’s COVID-19 tax and pension relief legislation, including the historic Families First Coronavirus Response Act, the Coronavirus Aid, Relief, and Economic Security (CARES) Act, and the COVID-19 tax relief included the Consolidated Appropriations Act, 2021.

Prior, Mark was senior tax counsel in the office of Sen. John Thune (R-SD), where he contributed to the development and drafting of key parts of the Tax Cuts and Jobs Act (TCJA). Mark also spent four years working as tax counsel to the House Ways and Means Committee under committee chairs Dave Camp (R-MI), Paul Ryan (R-WI) and Kevin Brady (R-TX).

Earlier, Mark served as deputy assistant secretary for the Department of the Treasury, Office of Legislative Affairs in the administration of President George W. Bush. In addition to his public service, Mark spent two years as vice president for tax and finance at the Retail Industry Leaders Association and practiced law in New York and Washington, D.C.

Mark started his career on Capitol Hill in 1995 as tax counsel to the House Small Business Committee and later to the Senate Committee on Small Business and Entrepreneurship, and he has served as an adjunct professor at Georgetown University’s McDonough School of Business.

Insights & Publications



  • LL.M., 1992, New York University School of Law
  • J.D., 1989, Georgetown University Law Center
  • B.S., 1986, Georgetown University


  • New York
  • Washington, D.C.