US President-elect Donald Trump has named Fox News host and military veteran Pete Hegseth as his secretary of defence.

Hegseth was deployed to Afghanistan with the US Army National Guard between 2011 and 2012 and spent 10 months at Camp Julien in Kabul.

Hegseth served as a trainer at the counterinsurgency centre at Camp Julien in Kabul, which was home to the International Security Assistance Force (ISAF).

He graduated from Harvard and Princeton universities and served in Iraq and Guantánamo in addition to Afghanistan.

In 2019, during Donald Trump's first presidency, he called on the president to pardon veterans accused of war crimes. Hegseth spoke about the soldiers' cases and their families on his show on Fox News.

Following Hegseth's efforts, that same year, Donald Trump pardoned a former US Army commando who was to stand trial for killing an Afghan suspected bomber. Another US Army soldier who was convicted of ordering the shooting of three Afghans and killing two of them, was pardoned.

The Reuters news agency called the appointment of Hegseth as defence secretary one of Trump's most surprising choices. He has a pessimistic view of NATO and has criticised the alliance's allies for being "weak”.

Hegseth is 44 years old, and Trump has touted him as a "tough, intelligent" person and a true believer in the "America First" slogan. "With Pitt at the helm, America's enemies must be on high alert. Our military will grow again, and America will never back down," Trump noted.

Hegseth has said that he left the US military in 2021 after the force sidelined him because of his political and religious views.

Trump's nominee for defence secretary must win a vote of confidence in the Senate to win the seat.