Vice Admiral Mark Hammond was named chief of the Australian Defence Force by Prime Minister Anthony Albanese on Monday.
He will take over in July from David Johnston, who has held the role since mid-2024.
"Vice Admiral Hammond has had a distinguished career spanning 40 years in the Royal Australian Navy," Mr Albanese told reporters in Canberra.
"Vice Admiral Hammond will continue to bring valuable insight to the role of chief of the Defence Force."
The incoming ADF boss joined the navy in 1986 as an electronics technician before becoming a naval officer two years later.
Throughout his nearly four decades in the military, he served on the Collins class of submarines, commanding the HMAS Farncomb across the Indo-Pacific, and was posted as an assistant naval attache in Washington DC.
Vice Admiral Hammond became head of the navy in July 2022, overseeing work on the multibillion-dollar AUKUS nuclear submarine deal, one of Australia's biggest defence projects.
The responsibility of the position was not lost on him, he said.
"This is probably the most humbling moment in my career,'' he said.
"I certainly look forward to serving with and for Australia's sailors, soldiers and aviators as their chief of defence force through the challenging times ahead."
Australian National University expert associate Jennifer Parker said while overseeing the AUKUS deal would be significant, there were other more pressing challenges the incoming chief needed to deal with.
"We will see increased demands on our defence force to operate both in the South China Sea, the wider Indo-Pacific and other areas of the world," she told AAP.
"Those demands will need to be balanced against trying to upgrade the defence force.
"AUKUS will be a key feature, but I don't think the chief of the Defence Force has been selected because of AUKUS."
The announcement comes before the government unveils its two-year defence strategy on Thursday.
The prime minister also named Susan Coyle, current chief of joint capabilities, as the next chief of the army.
Lieutenant General Coyle first enlisted as a soldier in the army reserves in 1987, and has since been deployed to East Timor, the Solomon Islands and Afghanistan.
In 2020, she was the first woman to command the joint task force for all Australian operations in the Middle East.
The current deputy chief of the navy, Rear Admiral Matthew Buckley, will be promoted to the top job, following the elevation of Vice Admiral Hammond.
Defence Industry Minister Pat Conroy said the appointment of Vice Admiral Hammond was significant for the defence force.
"He'll do a great job as we re-equip the Australian Defence Force to face those confronting strategic circumstances," he told ABC TV.
