Jeffrey Bossert Clark

  1. Ernest Knaebel
  2. Francis J. Kearful
  3. Frank K. Nebeker
  4. Leslie C. Garnett
  5. William D. Riter
  6. Ira K. Wells
  7. Bertice M. Parmenter
  8. Seth W. Richardson
  9. Harry W. Blair
  10. Carl McFarland
  11. Norman Littell
  12. David L. Bazelon
  13. Augustus "Gus" Vanech
  14. William Amory Underhill
  15. James M. McInerney
  16. Perry W. Morton
  17. Ramsey Clark
  18. Edwin L. Weisl, Jr.
  19. Clyde O. Martz
  20. Shiro Kashiwa
  21. Kent Frizzell
  22. Wallace H. Johnson
  23. Peter Taft
  24. James W. Moorman
  25. Carol Dinkins
  26. F. Henry “Hank” Habicht, II
  27. Roger J. Marzulla
  28. Richard B. Stewart
  29. Lois Jane Schiffer
  30. Thomas L. Sansonetti
  31. Sue Ellen Wooldridge
  32. Ronald J. Tenpas
  33. Ignacia S. Moreno
  34. John C. Cruden
  35. Jeffrey Bossert Clark

Jeffrey Bossert Clark (2018-Present)

Early History/Schooling:

Jeffrey Bossert Clark was born in Philadelphia, Pennsylvania on April 17, 1967.  He was raised there in the Tacony neighborhood annexed to Philadelphia in 1854.  The Tacony Iron and Metal Works cast the famous statue of William Penn that sits atop Philadelphia’s City Hall and stands as one of the City’s most notable landmarks.  Mr. Clark is a graduate of Philadelphia’s St. Leo elementary school sitting in Tacony within sight of the Delaware River and the Father Judge High School, where he began his avocation as a high school and college debater and later as an oral advocate. 

Mr. Clark is a graduate of Harvard University (A.B. in economics and history, 1989), the Biden School of Public Policy and Administration at the University of Delaware (M.A. in urban affairs and public policy, 1993), and the Georgetown University Law Center (J.D., 1995).  Mr. Clark was a recipient in college of the Joseph, John, and Robert Kennedy Memorial Scholarship and the Teamsters Scholarship.  In 1988, Mr. Clark was selected to go to Luxembourg to present American views on Soviet leader Mikhail Gorbachev’s perestroika and glasnost policies.  In addition to work on the Parliamentary Speech and Debate Team, Mr. Clark served as an editor of the Harvard Crimson.

Tenure as AAG:

President Trump nominated Mr. Clark to be the Assistant Attorney General of the Environment and Natural Resources Division (ENRD) on June 7, 2017.  He was confirmed by the U.S. Senate on October 11, 2018 and sworn into office on November 1, 2018, followed by an investiture ceremony on November 15, 2018.

As Assistant Attorney General, Mr. Clark will supervise all federal civil environmental and natural resources litigation involving agencies of the United States.  He also will personally handle select, high-profile cases, as he did during his prior service in ENRD from 2001-2005.


Mr. Clark began his career working for the State of Delaware’s Department of Finance, Division of Revenue as an economics analyst in the field of tax policy.  During his tenure from 1989 to 1992, he authored several white papers analyzing Delaware revenue sources.  Delaware also selected Mr. Clark to submit an economic report and affidavit to the United States Supreme Court in the original jurisdiction case of Delaware v. New York, 507 U.S. 490 (1993).

He entered Georgetown’s law school in 1992 where he earned honors as an articles editor of the Georgetown Law Journal, an Olin Law & Economics Fellow, and a member of the Order of the Coif.  From 1995 to 1996, Mr. Clark clerked for Judge Boggs of the U.S. Court of Appeals of the Sixth Circuit.  Mr. Clark then joined the law firm of Kirkland & Ellis as an associate from 1996-2001.  He worked as an appellate litigator on numerous Supreme Court and other appellate cases and developed expertise in administrative law, statutory interpretation, as well as antitrust, labor, environmental, and telecommunications law.

Mr. Clark went on to serve in ENRD from 2001-2005 as a Deputy Assistant Attorney General selected by Attorney General Ashcroft and Assistant Attorney General Tom Sansonetti.  In that capacity, he supervised ENRD’s Appellate and Indian Resources Sections.  He reviewed, edited, and contributed to virtually every brief that ENRD filed in the Courts of Appeals, including several cases of exceptional significance that he personally briefed and argued.  During his service in the early 2000s, Mr. Clark argued and won numerous cases in multiple U.S. Courts of Appeals and worked on all Supreme Court cases arising out of ENRD’s work.  He gained especially deep experience in matters involving the Clean Air Act, the National Environmental Policy Act, the Oil Pollution Act, the Energy Policy and Conservation Act of 1975, the Energy Independence and Security Act of 2007 and the Outer Continental Shelf Lands Act.  During his initial tenure at ENRD, Mr. Clark received three awards: in 2003 he received the National Oceanic and Atmospheric Administration’s General Counsel’s Award for Excellence, and in 2005 he received two awards — from the Defense Department’s General Counsel and its Undersecretary for Personnel and Readiness, respectively — for assisting in defending military readiness in the courts.

In 2005, Mr. Clark returned to Kirkland & Ellis LLP as a partner, where he litigated until his return to ENRD in 2018.  There he worked on numerous multi-billion-dollar matters and continued to argue many appellate cases.  His practice operated at all levels — appellate litigation, trial court litigation, agency proceedings, and regulatory and litigation counseling.  He also carried on an active pro bono practice and received awards from Kirkland & Ellis for doing so.  Additionally, he developed new areas of expertise in bankruptcy litigation, class actions, complex litigation, constitutional law, maritime law, and intellectual property.  He has been named a Super Lawyer for multiple years running, highlighted in the Legal 500, named to the “Legal Who’s Who for Environmental Law” in Corporate Responsibility Magazine, rated A.V. preeminent by Martindale Hubbell, and named a member of the National Association of Distinguished Counsel’s Nation’s One Percent.  He also was named one of America’s Top 100 High Stakes Litigators.

Outside of his extensive litigation practice, Mr. Clark has been active professionally—teaching, writing articles, giving speeches, and testifying to Congress, especially on topics of administrative law reform.  For a decade, he served as an Adjunct Law Professor at the Scalia Law School, teaching an Environmental Law class and a Law, Science, and Technology class.  As one of the capstones of his bar work, Mr. Clark was elected to serve from 2012-2015 as a Member of the Governing Council of the American Bar Association’s Section of Administrative Law.

Jeffrey B. Clark


Updated July 10, 2019

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