In an unexpected announcement that underscores ongoing turmoil in top U.S. defense leadership, the Pentagon disclosed Wednesday that United States Navy Secretary John Phelan is leaving his post effective immediately. The departure makes Phelan the first leader of a U.S. military branch to exit office during President Donald Trump’s second term, and adds to a growing string of high-profile departures and ousters among top defense officials.
No official explanation has been offered for the sudden exit of the Navy’s top civilian leader, which comes at a tense moment for the service: the U.S. Navy is currently enforcing a blockade of Iranian ports and intercepting vessels tied to the Tehran government across global waters, amid a fragile ceasefire in an ongoing regional conflict.
Phelan’s exit is the latest in a wave of leadership reshuffles at the Department of Defense, coming just weeks after Defense Secretary Pete Hegseth dismissed General Randy George, the Army’s highest-ranking uniformed officer. Since assuming office last year, Hegseth has removed a number of other top generals, admirals and senior defense leaders from their posts.
The abruptness of Phelan’s departure was highlighted by his public schedule just one day prior: on Tuesday, he spoke to a large gathering of sailors and defense industry representatives at the Navy’s annual Washington D.C. conference, and held press briefings to outline his upcoming policy agenda for the service.
Pentagon spokesman Sean Phelan confirmed the leadership change in a social media post, announcing that Undersecretary Hung Cao would take over as acting Navy Secretary immediately.
Cao, a 25-year veteran of the U.S. Navy with combat deployment experience, is no stranger to Republican politics. As a Trump-endorsed candidate in 2024, he mounted an unsuccessful bid to unseat Democratic Senator Tim Kaine in Virginia’s U.S. Senate race. Cao first came to the U.S. as a child refugee, fleeing communist rule in Vietnam with his family in the 1970s. During his Senate campaign, he drew sharp criticism of the Biden administration, comparing Cold War-era Vietnam’s communist government to Biden’s leadership. In a campaign video, he claimed the U.S. was “losing our country,” blaming Biden for the criminal investigations into former President Trump and highlighting issues including border security and retail crime.
Before his nomination as Navy Secretary by Trump in late 2024, Phelan had no prior military service nor previous civilian leadership experience within any branch of the U.S. armed forces. A prominent major donor to Trump’s 2024 campaign, Phelan made his career as the founder of Rugger Management LLC, a private investment firm. His only formal connection to the U.S. military prior to taking office was an advisory role with Spirit of America, a non-profit organization that provides support for defense initiatives focused on Ukraine and Taiwan.
As of Wednesday evening, The Associated Press had not succeeded in reaching Phelan’s office for a comment on his sudden departure.