Lloyd J. Austin III (2021–2025):
• Military Service: Austin is a retired four-star general with a 41-year career in the U.S. Army. He served as the commander of U.S. Central Command (CENTCOM) and was the first African American to hold the position of Secretary of Defense.
• Post-Military Career: After retiring, he joined the boards of several companies, including Raytheon Technologies.
• Confirmation: His appointment required a congressional waiver due to the statutory requirement for a seven-year gap between active military service and appointment as Secretary of Defense.
Mark Esper (2019–2020):
• Military Service: Esper is a former U.S. Army infantry officer who served in the Gulf War.
• Private Sector and Government Experience: He worked as a senior executive at Raytheon and served as the Secretary of the Army before becoming Secretary of Defense.
James Mattis (2017–2019):
• Military Service: Mattis is a retired four-star Marine Corps general with extensive combat experience, including leading U.S. Central Command.
• Confirmation: Like Austin, Mattis required a congressional waiver to serve as Secretary of Defense due to the seven-year post-service stipulation.
Ashton Carter (2015–2017):
• Academic and Government Service: Carter held degrees in physics and medieval history and had extensive experience in the Department of Defense in various capacities, including Deputy Secretary of Defense.
Chuck Hagel (2013–2015):
• Military Service: Hagel is a Vietnam War veteran who received two Purple Hearts for his service.
• Political Career: He served as a U.S. Senator from Nebraska before his appointment as Secretary of Defense.
Leon Panetta (2011–2013):
• Political and Government Service: Panetta served as a U.S. Representative, Director of the Office of Management and Budget, White House Chief of Staff, and Director of the CIA prior to becoming Secretary of Defense.
