Waltz, a Trump loyalist who also served in the National Guard as a colonel, has criticised Chinese activity in the Asia-Pacific and has voiced the need for the United States to be ready for a potential conflict in the region.
The national security adviser is a powerful role, which does not require Senate confirmation. Waltz will be responsible for briefing Trump on key national security issues and coordinating with different agencies.
While slamming the Biden administration for a disastrous withdrawal from Afghanistan in 2021, Waltz has publicly praised Trump's foreign policy views.
"Disruptors are often not nice ... frankly our national security establishment and certainly a lot of people that are dug into bad old habits in the Pentagon need that disruption," Waltz said during an event earlier this year.
"Donald Trump is that disruptor."
Waltz has a long history in Washington's political circles.
He was a defence policy director for defence secretaries Donald Rumsfeld and Robert Gates and was elected to Congress in 2018. He is the chairman of the House Armed Services subcommittee overseeing military logistics and also on the select committee on intelligence.
Elise Stefanik is an "America First fighter," Trump said. (AP PHOTO)
Earlier Elise Stefanik was appointed to serve as United States ambassador to the United Nations.
"I am honoured to nominate chairwoman Elise Stefanik to serve in my cabinet as US ambassador to the United Nations. Elise is an incredibly strong, tough, and smart America First fighter," Trump said.
Stefanik, 40, a New York representative and House Republican Conference chair, has been a fierce Trump ally.
The United Nations has been planning for Trump's return and the cuts to US funding and engagement with the world body that are likely to come with his second term as president.
Trump has offered few specifics about foreign policy in his second term but supporters say the force of his personality and his "peace through strength" approach will help bend foreign leaders to his will.
He has vowed to solve the war in Ukraine and is expected to give support to Israel in its conflicts with Hamas and Hezbollah in the Gaza Strip and southern Lebanon.
Lee Zeldin was appointed to head the Environmental Protection Agency. (AP PHOTO)
Trump also announced the appointment of Republican former Congressman Lee Zeldin, who often voted against legislation on green issues including a measure to stop oil companies from price gouging, to head the Environmental Protection Agency.
"He will ensure fair and swift deregulatory decisions that will be enacted in a way to unleash the power of American businesses, while at the same time maintaining the highest environmental standards, including the cleanest air and water on the planet," Trump said in a post on his social media platform Truth Social.
Trump has said he plans to begin rescinding EPA and Transportation Department vehicle pollution rules on his first day in office and is considering paring back or eliminating EV tax breaks and other incentives.
Trump also plans to rescind California's ability to set its own vehicle emissions rules, as he did in 2019.
As a candidate for New York governor in the 2022 election, Zeldin criticised the state's decision to join California's Zero Emission Vehicle program that vows to end the sale of gasoline-powered only vehicles by 2035.
"We will restore US energy dominance, revitalise our auto industry to bring back American jobs, and make the US the global leader of AI," Zeldin said on the X social media platform.
It is an honor to join President Trump's Cabinet as EPA Administrator.— Lee Zeldin (@leezeldin) We will restore US energy dominance, revitalize our auto industry to bring back American jobs, and make the US the global leader of AI. We will do so while protecting access to clean air and water. https://t.co/G5xMtYatnsNovember 11, 2024
Zeldin will have to be approved by the Senate, which regained a Republican majority in this month's election.