FILE -- Jon Meacham, the presidential historian and biographer, in New York on June 26, 2018. Meacham, best known for writing about past presidents like Andrew Jackson and George Bush, has helped shape some of Joe Biden's most significant speeches. (Nina Westervelt/The New York Times)

WASHINGTON — Jon Meacham — a Chattanooga native, McCallie School graduate and presidential historian and biographer best known for studying the lives of past presidents — has taken on a relatively unique role in a contemporary political moment: helping to write speeches for the next president.

Meacham has had a hand in crafting many of Joe Biden's biggest rhetorical moments, according to multiple sources, including helping to write the acceptance speech that Biden delivered Saturday night from Wilmington, Delaware, his first remarks as the president-elect.

In that address, Biden spoke of a mission "to rebuild the soul of America, to rebuild the backbone of this nation, the middle class, and to make America respected around the world again" and was widely credited with striking the right tone about bringing the country back together. The language echoed the title of Meacham's 2018 book, "The Soul of America: The Battle for Our Better Angels," which has long served as a touchstone for Biden, who has reached out to Meacham in the past to discuss passages he liked.

"To record history doesn't mean you are removed from it," Meacham said over the summer, noting that he had been friends with Biden for a long time.

Biden's speech-writing process is run by Mike Donilon, his longtime adviser. But behind the scenes, Meacham has been playing a larger role than was previously known, writing drafts of speeches and offering edits on others, including one Biden gave in Gettysburg, Pennsylvania, last month and his acceptance speech at the Democratic National Convention in August.

"President-elect Joe Biden wrote the speech he delivered to the American people on Saturday night, which laid out his vision for uniting and healing the nation," said TJ Ducklo, a spokesman for Biden.

"Given the significance of the speech, he consulted a number of important and diverse voices as part of his writing process, as he often does," Ducklo added. A Biden official said that Meacham was involved in discussions about the themes in the victory speech.

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Meacham, who has voted for presidents from both parties and wrote a favorable biography of former President George H.W. Bush, has played an unusual role during the 2020 campaign. He publicly endorsed Biden in an op-ed in The Washington Post in March and received a prime speaking slot at the Democratic convention.

In that speech, he addressed the nation from his home in Nashville, Tennessee, and warned that "our democracy is under assault from an incumbent more interested in himself than he is in the rest of us." He called the choice that voters faced in November "a choice that goes straight to the nature of the soul of America."

Meacham is not expected to join the administration. But his connection to Biden recalls historian Arthur M. Schlesinger Jr.'s relationship with President John F. Kennedy. Schlesinger worked for Kennedy's campaign and as a member of his White House staff, and later chronicled his presidency.

Biden's reliance on a historian stands in contrast with President Donald Trump's lack of interest in the past. Biden is known as a person who likes to use historical analogies in his public speeches and his own thinking, and historians have said that it made sense he would want someone like Meacham involved in the speech-writing process.

"The fear of that kind of work is you get labeled a court historian and are seen as being hyperpartisan," said Douglas Brinkley, a history professor at Rice University. "But if anyone can pull it off, Meacham can. He's liked by moderate Republicans. He's a bestselling writer. He's a wordsmith, and that's what Biden needs. He's probably able to keep a foot in both worlds."

Brinkley added that Meacham was uniquely suited to help Biden with weaving "patriotic lore" into his speeches.

Meacham declined to comment on his role.

During the Trump years, Meacham had also been a regular presence on MSNBC and NBC News broadcasts. But as of Monday, he was not a paid contributor at the network, according to two people familiar with the decision. Meacham was expected to return to NBC as an unpaid guest and could resume his paid role next year, possibly after the inauguration, the people said. NBC declined to comment.

Indeed, Meacham appeared on MSNBC before and after Biden's acceptance speech Saturday. About half an hour after Biden had concluded, anchor Brian Williams introduced Meacham by saying, "I'm not the historian that you are, and I don't have the Pulitzer that you do, but do you concur that is the way we are used to hearing from our presidents?"

"Absolutely," Meacham responded, without disclosing that he had been involved in the writing of the speech.

Shortly before Vice President-elect Kamala Harris and Biden took the stage, Meacham commented on the symbolism of a new administration featuring a 77-year-old institutionalist and a vice president-elect "who represents in many ways the changing demography of the country."

"It's poetic," Meacham said. "There's a lot of poetry tonight."