Trump’s selection of Powell to lead the central bank was driven largely by Treasury Secretary Steven Mnuchin. Powell’s appointment was very unusual, as he is not an economist. He had served in a past Republican White House but was first tapped to serve as a Fed governor by Obama. During his initial tenure at the Fed, Powell was seen as largely supportive of the slow-but-steady interest rate increase strategy used by then-Chair Janet L. Yellen.

Trump considered reappointing Yellen to the post, and she impressed him greatly during an interview, according to people briefed on their encounter. But advisers steered him away from renominating her, telling him that he should have his own person in the job.

The president also appeared hung up on Yellen’s height. He told aides on the National Economic Council on several occasions that the 5-foot-3-inch economist was not tall enough to lead the central bank, quizzing them on whether they agreed, current and former officials said.