U.S. Army Secretary Dan Driscoll has resigned from his position after about 18 months in the role. The news was confirmed by CBS, which reported that his departure followed months of conflict with Defense Secretary Pete Hegseth. Driscoll, 41, was known as President Donald Trump’s “drone guy” for his advocacy of advanced military technologies, and the White House previously praised him as “highly effective” in advancing Trump’s agenda and providing “outstanding leadership” during military operations. The BBC has reached out to the White House, Pentagon, and Army for official comments on his resignation. Driscoll is the latest in a series of high-profile military officials to leave their posts recently. This includes Navy Secretary John Phelan, who abruptly resigned in April, as well as Army Chief of Staff Randy George, Army Gen David Hodne, and Maj Gen William Green. Since taking over at the Pentagon, Defense Secretary Pete Hegseth has dismissed more than a dozen senior military officers, including the chief of naval operations and the Air Force’s vice-chief of staff. While the specific reasons for the tension between Driscoll and Hegseth remain unclear, CBS reported that Driscoll is close to George, who was reportedly asked by Hegseth to resign. The position of Army Secretary is the highest civilian role in the U.S. Army, overseeing active duty forces, the National Guard, and reserve soldiers. Driscoll previously served in the Army, becoming an officer in 2007 and leading a cavalry platoon that deployed to Iraq in 2009. During his time as Army Secretary, he became prominent for his support of emerging battlefield technologies, such as drones, which earned him the nickname “drone guy.” He also played a key role in Trump’s deployment of the National Guard to U.S. cities and took on the acting director role at the Bureau of Alcohol, Tobacco, Firearms and Explosives. Driscoll was also a central figure in Trump’s efforts to end the Russia-Ukraine war, traveling abroad and meeting with Ukrainian President Volodymyr Zelensky. Additionally, he is a close ally of Vice President JD Vance, whom he met during their time at Yale Law School. His resignation comes amid a period of significant turnover in the Pentagon, raising questions about the stability and direction of U.S. military leadership under the current administration.