Preston Wells Griffith III is an American diplomat who has served as the Representative of the United States to the International Atomic Energy Agency and to the Vienna Office of the United Nations since 2026 with the rank of ambassador.
He previously served as the under secretary of energy and as the senior director on the National Security Council of the White House Office during the first and second Trump administrations.
Early life and education
Griffith is a native of Mobile, Alabama. He earned a Bachelor of Arts in history with a minor in modern languages from the Virginia Military Institute in Lexington, Virginia, and a Juris Doctor from the Mississippi College School of Law in Jackson, Mississippi.
Political career
Griffith worked on United States House and Senate campaigns across the Southeast. He served as executive director of the Mississippi Republican Party during the governorship of Haley Barbour.
He sought the Republican nomination for Alabama's 1st congressional district in the 2013 special election called after the resignation of Jo Bonner. He finished fifth in the September 24, 2013 primary with 5,758 votes, or 11 percent.
He went on to serve as deputy political director of Scott Walker's presidential campaign. He then went on to serve as director for battleground states for Donald J. Trump for President, and as deputy chief of staff and senior adviser to Reince Priebus at the Republican National Committee.
First Trump administration
Griffith joined the Department of Energy on January 20, 2017 as a senior White House adviser and subsequently served as principal deputy assistant secretary and acting assistant secretary in the Office of International Affairs. During this period, he concurrently served as the Vice Chair of the Governing Board of the International Energy Agency.
Griffith transferred to the White House Office in April 2019, where he was special assistant to the president and senior director for energy and environment on the National Security Council and the National Economic Council. He later became managing director and senior adviser to the chief executive officer of the United States International Development Finance Corporation.
Under Secretary of Energy
Trump announced on January 16, 2025 that he would nominate Griffith as Under Secretary of Energy. The Senate confirmed him on July 9, 2025 by 54 votes to 43.
In October 2025, E&E News reported, citing lobbyists and department staff, that Griffith had been placed on paid leave and was no longer on the job, without having resigned or been formally dismissed.
On October 17, 2025, Energy Secretary Chris Wright named Alex Fitzsimmons, then head of the department's Office of Cybersecurity, Energy Security, and Emergency Response, as acting under secretary.
Ambassador to international organizations in Vienna
Trump submitted Griffith's name to the Senate on March 2, 2026, nominating him to serve concurrently as Representative of the United States to the Vienna Office of the United Nations and as Representative of the United States to the International Atomic Energy Agency, with the rank of ambassador.
On August 7, 2026, the Senate approved Griffith's nomination in a vote of 51 votes in favor to 47 against.
References
Further reading
External links
U.S. Mission to International Organizations in Vienna