President-elect Donald J. Trump boasted throughout the presidential campaign of his loyalty as a singular quality. “Folks, look, I’m a loyal person,” Mr. Trump said at a CNN town hall in April, explaining why he would not rid his campaign of a staff member who was under fire.

Loyalty appears to be paramount for Mr. Trump, until it isn’t.

Some of Mr. Trump's earliest supporters — among them Rudolph W. Giuliani, Gov. Chris Christie of New Jersey, Sarah Palin, Newt Gingrich and Mike Huckabee — have not fared well in the job sweepstakes. On top of that, they have been left in the December cold while Mitt Romney, a leader of the “never Trump” movement, has been wooed by the president-elect’s advisers for secretary of state.

“It kind of reminds me of the Reagan administration,” said Roger Stone, a long-serving informal adviser to Mr. Trump who met with him at Trump Tower last week. “We used to have a running joke where it was news if somebody who supported Reagan got a job.”