Bannon's new position was listed above the announcement of RNC chair Reince Priebus as Trump's new chief of staff on a statement issued Sunday. It said Bannon and Priebus would be "equal partners."
There was no shortage of reaction.
Evan McMullin, who ran for the White House as an independent and won 21 percent of the vote in Utah:
John Weaver, a top strategist for Ohio Governor John Kasich:
Jonathan Greenblatt, chief executive of the Anti-Defamation League:
Greenblatt praised Trump's choice of Priebus, but bashed Bannon's new role.
"It is a sad day when a man who presided over the premier website of the 'alt-right' — a loose-knit group of white nationalists and unabashed anti-Semites and racists — is slated to be a senior staff member in the 'people's house,'" he added.
Joel Pollak, who worked for Bannon at Breitbart:
Pollak told NBC News that the soon-to-be White House chief strategist was not anti-Semitic, racist or anti-woman.
He called Bannon a champion of a diverse range of conservative voices.
Marion Le Pen, the granddaughter of the founder of France's far-right National Front party:
The Council on American-Islamic Relations:
CAIR National Executive Director Nihad Awad that Bannon's appointment adds fuel to the fire of racial and ethnic hatred and division in America.
"The appointment of Stephen Bannon as a top Trump administration strategist sends the disturbing message that anti-Muslim conspiracy theories and White nationalist ideology will be welcome in the White House," Awad added. "We urge President-elect Trump to reconsider this ill-advised appointment if he truly seeks to unite Americans."
The organization said Bannon "promoted conspiracy theories that "paint a dark and paranoid picture" of American Muslims. Breitbart News traffics in misogynistic and racist stories targeting women, people of color and immigrants."
A spokesman for Harry Reid, the Senate minority leader:
"President-elect Trump's choice of Steve Bannon as his top aide signals that white supremacists will be represented at the highest levels in Trump's White House," Adam Jentleson said. "It is easy to see why the KKK views Trump as their champion when Trump appoints one of the foremost peddlers of white supremacist themes and rhetoric as his top aide ... Sworn testimony in a court case alleged that Bannon committed violent domestic abuse and stated that he 'didn't want the girls going to school with Jews.'"
Scot Vorse, a longtime friend and ex-business partner of Bannon:
Vorse drew a distinction between what he described as Bannon's inclusive personal views and Breitbart's "provocative" ones.
The Southern Poverty Law Center:
U.K.-based journalist Andre Walker:
The New York Observer columnist added that Bannon would be "superb" in his new position.