By Tess Ikonomou and John Kidman in Canberra

Defence boss Greg Moriarty will succeed Kevin Rudd as Australian ambassador to the US, taking over the key role in shoring up the two nations’ security ties.

Mr Moriarty has led the department since late 2017 and previously served as chief of staff to then-Liberal prime minister Malcolm Turnbull.

Prime Minister Anthony Albanese made the announcement on Sunday ahead of Dr Rudd’s scheduled exit from the role at the end of March.

“Mr Moriarty is an outstanding Australian public servant,” Mr Albanese told ABC’s Insiders program.

“I’ve been impressed by the dignified way in which he handles himself, by his connections in the United States.

“The AUKUS relationship is central to our relationship with the United States and he’s in a very strong position to be on top of all of that detail.”

Under the security pact, Australia has been promised at least three Virginia-class submarines from the US in the early 2030s, before a new fleet of vessels is built for delivery from the 2040s.

The $368 billion submarine deal with the US was cast into doubt when a Pentagon review was launched, although the Trump administration has since reiterated its support for the pact.

As the US struggles to meet its submarine production target, security experts have raised concerns Australia might not be sold the boats.

Dr Rudd, a former Labor prime minister, was appointed in 2023 but resigned from the role a year early.

He faced a tumultuous period under the Republican administration, having previously been a strident critic of Mr Trump.

Dr Rudd pointed to Mr Moriarty’s decades of experience working on Australia’s relationship with the US and as a diplomat.

“He is deeply familiar with AUKUS and will be a critical leader in driving AUKUS implementation,” he said.

“The relationship could be in no better hands.”

Mr Albanese said Dr Rudd could look back on his time as ambassador “with real pride”.

Democratic congressman Joe Courtney, co-chair of the Congressional Friends of Australia Caucus, said the appointment was “great news for both nations”.

“His deep knowledge of and connections in Washington and across the country ensures that there will be a zero learning curve for the duties and mission of this critical position,” he said.

“There is still much work to be done to strengthen the alliance, and he is well-positioned to succeed on that mission.”

Opposition foreign affairs spokeswoman Michaelia Cash also welcomed the appointment, describing Mr Moriarty as a “safe pair of hands”.

The defence boss previously served as Australian ambassador to Iran and then Indonesia before returning to Canberra.

Mr Trump recently sparked outrage after claiming troops from NATO countries had stayed away from the front line in Afghanistan, leading to condemnation from UK Prime Minister Keir Starmer and other allies.

Forty-seven Australians were killed in the 20-year conflict, while 261 of the nation’s personnel were wounded before troops were withdrawn in mid-2021.

Mr Albanese labelled Mr Trump’s comments “unacceptable” while noting the US president had since walked back the remarks.

“Those 47 Australian families, who will be hurting by these comments, they deserve our absolute respect, our admiration,” he said.

RSL national president Peter Tinley slammed the US president’s remarks as factually wrong, historically ignorant and deeply offensive.

Mr Trump on Sunday morning posted a message on Truth Social praising the “great and very brave soldiers of the United Kingdom” and said they “were among the greatest of all warriors”.