WASHINGTON — The F.B.I. director, James B. Comey, sometimes rattles off the exact amount of time left in his decade-long term as if he is eagerly watching the clock.

The next six years, nine months and 30 days until Sept. 4, 2023, look a lot more difficult lately.

Depending on who wins the election, Mr. Comey will work for either a man who accused him of being part of a rigged criminal justice system or a woman who has criticized his decisions as “deeply troubling” and whose surrogates accused him of committing a stunning violation of longstanding principles of fairness.

Friends and colleagues say that, despite a controversy that has entangled the F.B.I. in presidential politics, Mr. Comey feels no pressure to leave office and has no plans to do so. But, as one colleague recalled Mr. Comey saying recently, “It’s going to be awkward.”

Things will be particularly awkward if Hillary Clinton wins, those close to her and to Mr. Comey acknowledge. His decision, in the campaign’s final days, to make public an F.B.I. inquiry into emails belonging to one of Mrs. Clinton’s aides renewed a controversy that she thought she had put behind her. He left her little time to resolve it, and provided little more than a vaguely written letter for her to rebut.