White House chief strategist Steve Bannon is the latest top aide of President Donald Trump to leave his post.
Press Secretary Sarah Huckabee Sanders confirmed that Friday was his last day.
His exit follows a review of his position by White House Chief of Staff John Kelly.
Mr Bannon, a right-wing nationalist and former head of Breitbart.com, helped shape the “America First” message of Mr Trump’s election campaign.
But critics had accused the 63-year-old of harbouring anti-Semitic and white supremacist views.
Mr Bannon is known to have competed for influence in the West Wing against more moderate factions, including members of the Trump family.
Mr Trump raised eyebrows earlier this year when he elevated Mr Bannon to the National Security Council, the main group advising the president on national security and foreign affairs.
But he was subsequently removed from the council in a move that was seen as a sign of National Security Adviser HR McMaster’s growing influence over the president.
Mr Bannon has reportedly feuded with Mr McMaster as well as Gary Cohn, the director of the president’s National Economic Council and a former Goldman Sachs chief viewed as a globalist.
Mr Cohn, along with President Trump’s son-in-law, Jared Kushner, and daughter, Ivanka Trump, were viewed as threats to Mr Bannon’s White House agenda.