Mark Thomas Esper is an American politician and manufacturing executive who served as the 27th United States secretary of defense from 2019 to 2020. A member of the Republican Party, he had previously served as the 23rd U.S. secretary of the Army from November 2017 to July 2019.
A West Point graduate, Esper joined the United States Army and saw combat during the Gulf War as an infantry officer with the 101st Airborne Division. Esper subsequently served in the 82nd Airborne Division and the Army National Guard. After leaving military service, he served as chief of staff at the Heritage Foundation; a congressional staffer; a deputy assistant secretary of defense; and a senior executive for the Aerospace Industries Association, the Global Intellectual Property Center, and the U.S. Chamber of Commerce. Immediately before joining the Trump administration, Esper lobbied for defense contractor Raytheon as its vice president of government relations.
