WASHINGTON, D.C. — The Pentagon announced that Secretary of the Navy John Phelan is leaving his position, with Navy Undersecretary Hung Cao set to become acting secretary of the Navy. The Pentagon provided no reason for the departure.

"On behalf of the Secretary of War and Deputy Secretary of War, we are grateful to Secretary Phelan for his service to the Department and the United States Navy. We wish him well in his future endeavors," Chief Pentagon Spokesman Sean Parnell wrote, describing Phelan as "departing the administration, effective immediately."

A day before his departure, Phelan addressed sailors and industry professionals at the Navy's annual conference in Washington, D.C., delivering a keynote address and speaking with reporters about his ongoing agenda. At a media roundtable, he discussed the Navy's prioritizing of ship building capacity and the service's plan to double its vessel requests, according to the fiscal year 2027 defense budget request.

Phelan had not served in the military or held a civilian leadership role in the service before President Donald Trump nominated him for secretary in late 2024. He was a major donor to Trump's campaign and founded the private investment firm Rugger Management LLC. According to his biography, Phelan's primary exposure to the military came from an advisory position he held on Spirit of America, a non-profit that supported the defense of Ukraine and Taiwan.

His departure came weeks after Defense Secretary Pete Hegseth fired the Army's top officer, Gen. Randy George, and two other top Army generals.

Cao, a former Virginia Senate candidate, graduated from the United States Naval Academy. He deployed with special operations forces to Iraq, Afghanistan, and Somalia during a 25-year military career.