Mr. Caputo had been passed over for a job early in the administration, according to a person with knowledge of the process, but he contacted administration officials in the past month expressing renewed interest in a position. Mr. Caputo, who is from western New York, has remained friendly with Dan Scavino, another New Yorker and one of the few original campaign aides still on the White House staff. Mr. Scavino played a role in reconnecting Mr. Trump and Mr. Caputo last year, people familiar with the discussion said, which put Mr. Caputo on the president’s radar.

Trump allies heralded the move as in line with the hiring the administration should have done from the beginning: appointing officials devoted to Mr. Trump and his agenda. They described Mr. Caputo as a media-savvy operative who credits himself with good relationships with many journalists.

Critics said a pandemic was no time to rely on hyperpartisans.

“In a crisis, the public is looking for credible, nonpartisan voices with real expertise,” said Dan Pfeiffer, a former White House communications director for President Barack Obama. “Picking a partisan loyalist with a history of promoting conspiracy theories is the exact opposite of the right thing to do but it is very much on brand.”

Mr. Caputo declined to comment for this article, which is based on interviews with six administration officials and others with knowledge of his hiring.

In the decades since Mr. Trump began flirting with running for office, Mr. Caputo has played a role in encouraging him. A protégé of the operative and self-described “dirty trickster” Roger J. Stone Jr., Mr. Caputo has known Mr. Trump since the 1980s, when he briefly worked for a lobbying and political consulting firm started by Mr. Stone and two other Republican operatives, Charlie Black and Paul Manafort. Mr. Manafort went on to run Mr. Trump’s campaign for months and was sentenced last year to more than seven years in prison on a pair of financial and tax fraud convictions.