Stephen Anthony Cambone was the first United States Under Secretary of Defense for Intelligence, a post created in March 2003. Cambone first came to the attention of the public at large during the testimony of Major General Antonio Taguba before the U.S. Senate Armed Services Committee, where he disputed the General's statement that prison guards were under the effective control of military intelligence personnel and interrogators. Cambone resigned at the beginning of 2007 and was replaced by James R. Clapper, Jr., former head of the Defense Intelligence Agency (DIA) and the National Geospatial-Intelligence Agency. Cambone was associated with the Project for the New American Century, participating in the study which resulted in the writing of the report Rebuilding America's Defenses.
Michèle Angélique Flournoy is an American defense policy advisor who served as deputy assistant secretary of defense for strategy under President Bill Clinton and under secretary of defense for policy under President Barack Obama.
Ashton Baldwin Carter was an American government official and academic who served as the 25th United States secretary of defense from February 2015 to January 2017. He later served as director of the Belfer Center for Science & International Affairs at Harvard Kennedy School.
Lloyd James Austin III is a retired United States Army officer and served as the 28th United States secretary of defense from January 22, 2021 to January 20, 2025.
Eric Steven Edelman is an American diplomat who served as Under Secretary of Defense for Policy (2005–2009), U.S. Ambassador to Turkey (2003–2005), U.S. Ambassador to the Republic of Finland (1998–2001), and Principal Deputy Assistant to the Vice President for National Security Affairs (2001–2003). A career Foreign Service Officer, Edelman entered the Senior Foreign Service in 1992. He is a recipient of the Secretary of Defense's award for Distinguished Civilian Service (1993) and the State Department's Superior Honor Award.
Kurt Michael Campbell is an American diplomat and businessman serving as the United States deputy secretary of state since 2024. He previously served as deputy assistant advisor to President Biden and National Security Council coordinator for the Indo-Pacific from 2021 to 2024. In this capacity, Campbell had been referred to as the Biden administration's "Asia coordinator" or "Asia czar"—chief architect of Joe Biden's Asia strategy.
Michael Bruce Donley is a United States government official who is the director of administration and management in the Office of the Secretary of Defense since May 2021, having served in the same position from 2005 to 2008. In the Bush and Obama administrations, Donley served as the 22nd secretary of the Air Force, amongst other positions. Donley has 30 years of experience in the national security community, including service on the staff of the United States Senate, White House and The Pentagon.
Celeste Ann Wallander is an American international relations advisor who currently serves as assistant secretary of defense for international security affairs at the United States Department of Defense.
Robert Orton Work is an American national security professional who served as the 32nd United States Deputy Secretary of Defense for both the Obama and Trump administrations from 2014 to 2017. Prior to that, Work was the United States Under Secretary of the Navy from 2009 to 2013, and before that served as a colonel in the United States Marine Corps; Work retired in 2001 and worked as a civilian at the Center for Strategic and Budgetary Assessments (CSBA) and the George Washington University in various positions relating to military and strategic study. From 2013 to 2014, he was the CEO of the Center for a New American Security (CNAS). After his time as Deputy Secretary of Defense, he went on to serve on the board of Raytheon. As of October 2023, he serves on the Special Competitive Studies Project's board of advisors.
In the United States, the Assistant Secretary of Defense for International Security Affairs or ASD (ISA) is the principal advisor to the Under Secretary of Defense for Policy (USD (P)) and the United States Secretary of Defense on international security strategy and policy on issues of Department of Defense (DoD) interest related to the governments and defense establishments of the nations and international organizations of Europe (including the North Atlantic Treaty Organization), the Middle East, Africa, and the Western Hemisphere. The ASD (ISA) also oversees security cooperation programs and foreign military sales programs in these regions. Despite the broad title of the office, the ASD (ISA) does not develop policy related to Asia, the Pacific region, Latin America, or South America.
Avril Danica Haines is an American lawyer who served as the director of national intelligence in the Biden administration. She is the first woman to serve in this role. Haines previously was Deputy National Security Advisor and deputy director of the Central Intelligence Agency (CIA) in the Obama administration. Prior to her appointment to the CIA, she was Deputy Counsel to the President for National Security Affairs in the Office of White House Counsel.
Elizabeth D. Sherwood-Randall is an American national security and energy leader, public servant, educator, and author who served as the 11th United States Homeland Security Advisor to President Joe Biden from 2021-2025. She previously served in both the Clinton and Obama administrations and held appointments at academic institutions and think tanks.
Colin Hackett Kahl is an American political scientist who served as under secretary of defense for policy in the Biden administration from April 28, 2021, to July 17, 2023. Previously, he served as national security advisor to the vice president under then-Vice President Joe Biden (2014–2017). After the Obama administration, Kahl served as a Steven C. Házy Senior Fellow at Stanford University.
Christine E. Wormuth is an American defense official and career civil servant who served as the United States secretary of the Army from 2021 to 2025. A member of the Democratic Party, she is the first female United States secretary of the Army.
The United States Department of Defense China Task Force was announced by the United States president Joe Biden on February 10, 2021. Biden said the task force would help the United States "win the competition of the future" with China. According to the DOD News service, the task force will be led by Ely Ratner, an assistant to US Secretary of Defense Lloyd Austin III. On the day the task force was announced, Chinese leader Xi Jinping said that China sought cooperation with the United States, but that confrontation would be "definitely catastrophic for both countries and the world."
Mara Elizabeth Karlin is an American foreign policy and defense advisor. In April 2021, President Joe Biden nominated Karlin to serve as the Assistant Secretary of Defense for Strategy, Plans and Capabilities. She was confirmed by the U.S. Senate by voice vote on August 9, 2021. Previously, she served as the Acting Assistant Secretary of Defense for International Security Affairs. In her role, she served as the main advisor to Secretary of Defense Lloyd Austin on U.S. security policies related to every country in Europe, the Middle East, Africa, Eurasia, and the Western Hemisphere. Her portfolio included shaping U.S. defense policy related to NATO.
Melissa Griffin Dalton is an American defense official who is serving as the under secretary of the Air Force. She previously served as the assistant secretary of defense for homeland defense and hemispheric affairs in the Biden administration.
Alexandra Nicole Baker, known as Sasha Baker, is an American policy advisor who served as deputy under secretary of defense for policy at the Department of Defense.
Laura D. Taylor-Kale is an American foreign policy and economic advisor. She is the US Assistant Secretary of Defense for Industrial Base Policy.
