Trump, continuing to build his Cabinet as he prepares to take office on Jan. 20, said Oklahoma Attorney General Scott Pruitt, 48, would be nominated to head the Environmental Protection Agency.
Pruitt sued the EPA in a bid to undo a key regulation under outgoing President Barack Obama that would curb greenhouse gas emissions blamed for climate change, mainly from coal-fired power plants.
Trump tapped retired Marine Corps General John Kelly, 66, for secretary of the Department of Homeland Security, whose responsibilities include immigration.
Kelly, the third retired general named by Trump to a senior administration post, last year told Congress that a lack of security on the US-Mexican border posed a threat to the United States.
Trump's transition team said Republican Iowa Governor Terry Branstad, 70, who has boasted of close ties to Beijing's leaders, was picked as US ambassador to China.
In addition, transition officials said Linda McMahon, 68, former CEO of professional wrestling company WWE and wife of wrestling kingpin Vince McMahon, was Trump's choice to head the Small Business Administration.
Trump has taken part in WWE events in the past and has close ties to the McMahons. He is a member of the WWE Hall of Fame.
All four posts require Senate confirmation.