On Wednesday, Trump said he would nominate Gaetz to serve as US attorney general, describing him as a "deeply gifted and tenacious attorney," who during his term in Congress had pushed for "desperately needed reform at the Department of Justice."
Senior department officials called the decision "insane," "truly stunning" and "laughable."
"How many other prospective attorneys general had previous experience as the subject of a criminal investigation?" one of the department employees was quoted as saying, while another said Gaetz was "the least qualified person" ever nominated for a position in the department.
Gaetz, who was the subject of a federal sex trafficking investigation that ended without charges, has regularly attacked both the Justice Department and the FBI, including calling for the FBI to be defunded and abolished, US media said.