US Navy secretary John Phelan has stepped down with immediate effect, the Pentagon announced on Wednesday, marking the first departure of a military service chief during Donald Trump’s second term and the latest in a series of leadership changes at the department of defense.
Pentagon spokesperson Sean Parnell confirmed the move, saying Phelan was “departing the administration, effective immediately” and adding, “We are grateful to Secretary Phelan for his service to the Department and the United States Navy”.
No reason was given for his sudden resignation.
Phelan’s exit comes at a sensitive time, with the US Navy actively involved in enforcing a blockade of Iranian ports and targeting vessels linked to Tehran amid a fragile ceasefire in the Iran conflict.
The US Navy has also maintained a strong operational presence in key global waterways, including the Strait of Hormuz and surrounding maritime routes.
Hung Cao takes charge as acting Navy chief
Hung Cao, a former Navy combat officer and political candidate backed by Trump, will take over as acting secretary of the Navy.
Cao, a 25-year Navy veteran who served in Iraq, Afghanistan and Somalia, had earlier run unsuccessful campaigns for the US Senate and House in Virginia.
Since becoming undersecretary, he has backed efforts such as reinstating service members who refused Covid-19 vaccination mandates.
Part of wider Pentagon reshuffle
Phelan’s exit adds to a growing list of top-level changes at the Pentagon. In recent weeks, defence secretary Pete Hegseth has removed several senior military leaders, including the Army’s top officer Gen Randy George, as well as other generals and admirals.
Earlier, high-profile dismissals included Ad. Lisa Franchetti and Gen Charles “CQ” Brown Jr., reflecting a broader shake-up in military leadership since early 2025.
Notably, Phelan had appeared publicly just a day earlier at a Navy conference in Washington, where he addressed sailors and industry leaders and discussed shipbuilding and budget priorities.
Exit comes amid escalating regional tensions
The leadership change coincides with heightened tensions in the Strait of Hormuz, where recent attacks on commercial vessels and US enforcement of a naval blockade have raised concerns over the stability of a ceasefire with Iran.
The US has maintained the blockade even after extending the truce, while Iran has criticised the move as a violation of ceasefire terms and has yet to commit to fresh talks.
With multiple US aircraft carriers deployed in or heading to the Middle East, the US Navy remains central to any potential escalation if negotiations fail.
