WASHINGTON — President-elect Joseph R. Biden Jr. is delivering a message of cooperation and conciliation as he prepares to move into the White House.
It is Mike Donilon’s message.
A veteran Democratic strategist, pollster and media specialist, Mr. Donilon was Mr. Biden’s chief strategist during the 2020 campaign, helping the candidate develop the central theme that defeated President Trump: a fight for the soul of the nation.
He helped Mr. Biden frame the race against Mr. Trump as one about the character of the candidates, focusing the campaign’s advertising and Mr. Biden’s speeches on the contrast with Mr. Trump’s erratic and abusive behavior during four years in the Oval Office.
Now, as a senior adviser to Mr. Biden in the White House, Mr. Donilon will be the defender of the Biden brand. It will be his job to ensure that the new president weathers the crosscurrents in Washington as he battles Republicans in Congress and seeks to calm tensions between liberals and moderates in his own party.
“My message is, ‘I will work with you,’” Mr. Biden said this week of his intention to find ways to compromise with Republicans, even if they have so far refused to accept his victory.
That will be a challenge, especially after an election that has left the Senate almost evenly divided and reduced the Democratic majority in the House. But people close to Mr. Donilon say his long and close relationship with Mr. Biden makes him the perfect person to serve in that role.
“Mike is a brilliant message strategist with a deep understanding of, and loyalty to, Joe Biden,” said David Axelrod, who served in a similar role for President Barack Obama. “His inspiration from the beginning about framing the race as one about character proved out. And he shepherded it with great skill, discipline and even poetry.”
Mr. Axelrod said it was indispensable for someone like Mr. Donilon to have the trust of the president.
“Mike has that with Biden,” he said. “He will be the keeper of the narrative.”
In addition to being by Mr. Biden’s side for years, Mr. Donilon has been at the center of Democratic politics for decades. He has worked on six presidential campaigns, and transition officials said he was part of more than 25 winning campaigns for Senate, House, governor and mayor.
He worked in the late 1980s to help L. Douglas Wilder of Virginia become the country’s first elected African-American governor, a history-making campaign that helped pave the way for Mr. Donilon’s career on the national stage.
He was part of Bill Clinton’s presidential campaign in 1992, and was a key consultant on a series of Democratic campaigns for Senate and governor, including those of Gov. Jon Corzine of New Jersey, Senator Bill Nelson of Florida, Senator Christopher J. Dodd of Connecticut and Senator John Edwards of North Carolina.
Mr. Donilon is also an ad-maker and message guru who worked for AKPD, the firm founded by Mr. Axelrod and three others, including David Plouffe, a key strategist for Mr. Obama. His creation of independent ads for former Senator Claire McCaskill of Missouri helped her win her seat.
When Mr. Biden became vice president in 2009, Mr. Donilon became one of his top aides.
A graduate of Georgetown University and Georgetown University Law Center, Mr. Donilon had been the managing director of the Biden Institute and an assistant professor at the University of Delaware. He is also one of three brothers who have spent years in the public eye.
Tom Donilon, a veteran diplomat and national security expert, was a key confidant to Mr. Obama and served for several years as his national security adviser. He was also the chief of staff at the State Department and could join his brother in some role in the Biden administration.
Terrence Donilon is the secretary for communications and public affairs — essentially the chief spokesman — for the Archdiocese of Boston.