The firing of US Navy Secretary John Phelan is the latest in a shakeup of the American military during the war on Iran, now in its eighth week.

The Pentagon said Phelan would leave office immediately.

“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,” said chief Pentagon spokesperson Sean Parnell. “We wish him well in his future endeavours”.

His firing comes at a critical moment, with US naval forces enforcing a blockade on Iranian ports and ships, and maintaining a heavy presence around the Strait of Hormuz, through which 20 percent of the world’s oil and gas passes during peacetime.

Although the Pentagon gave no official reason for the dismissal, reports indicate the decision was linked to internal disputes, including tensions with Defense Secretary Pete Hegseth.

Phelan’s removal is part of a broader pattern of dismissals and restructuring within the US military under President Donald Trump’s administration – including during the current war.

So, who is John Phelan, and what impact could his firing have on US military strategy?

Who is John Phelan?

As the US Navy’s top civilian official, Phelan had various responsibilities, including overseeing recruiting, mobilising and organising, as well as construction and repair of ships and military equipment.

He was appointed in 2024 as a political ally of Trump, despite having no prior military or defence leadership experience.

Before entering government, Phelan was a businessman and investment executive, as well as a major Republican donor and fundraiser — a background that is fairly common among Trump appointees and advisers. The US president’s two top diplomatic negotiators, for instance, are Steve Witkoff — a real estate businessman with no prior diplomatic experience – and Trump’s son-in-law, Jared Kushner.

According to the Reuters news agency, Phelan’s tenure quickly became controversial. He faced criticism for moving too slowly on shipbuilding reforms and for strained relationships with key Pentagon figures, including Hegseth and his deputy, Steve Feinberg.

In addition, Phelan was reportedly under an ethics investigation, which may have weakened his standing in the administration.

Navy Undersecretary Hung Cao, who was also reported to have a difficult relationship with Phelan, has become acting secretary. Fifty-four-year-old Cao is a 25-year Navy veteran who previously ran as a Republican candidate for the US Senate and House of Representatives in 2022 and 2024 respectively, but was unsuccessful on both occasions.

Democrats have criticised Phelan’s removal, calling it “troubling”.

“I am concerned it is yet another example of the instability and dysfunction that have come to define the Department of Defense under President Trump and Secretary Hegseth,” said Senator Jack Reed, the top Democrat on the Senate Armed Services Committee.

Who else has the Trump administration fired since the war with Iran began?

Phelan’s removal is the latest in a series of senior military leaders being fired or are leaving during the US-Israeli war on Iran, in addition to others since Trump was re-elected.

Among the most notable dismissals was Army Chief of Staff General Randy A. George, in the first week of April. George was appointed in 2023 under former US President Joe Biden.

According to reports, Hegseth also fired the head of the Army’s Transformation and Training Command, a unit concerned with modernising the army, and the Army’s chief of chaplains. The Pentagon has not confirmed their dismissal.

Why is Phelan’s dismissal significant?

The 62-year-old’s removal comes during a fragile ceasefire with Iran, as the ⁠⁠US continues to move more naval assets into the region.

The Navy is central to enforcing Trump’s blockade of Iranian ports to restrict Iran’s oil exports and apply economic pressure on Tehran, as the US president looks eager to wrap up the war, which is deeply unpopular to many Americans.

However, there are no indications that Trump is willing to end the blockade or other naval operations in the Strait of Hormuz, as negotiations between Washington and Tehran have come to a standstill.

Tensions have escalated in recent days after the US military seized an Iranian container ship. The US claimed it was attempting to sail from the Arabian Sea through the Strait of Hormuz to the Iranian port of Bandar Abbas.

Tehran responded by describing the attack and hijack as an act of “piracy”.

Iran has since captured two cargo ships and fired at another.