Steve Bannon, Donald Trump's ex-chief strategist, has stepped down from the right-wing Breitbart News organisation where he built his reputation.
The move comes amid a furore over remarks he reportedly made about President Donald Trump's son.
He described a meeting Donald Trump Jr held in New York with a Russian lawyer during the 2016 presidential election campaign as "treasonous".
He was one of Mr Trump's most trusted - and controversial - aides.
But he left his post last summer after reports of a power struggle among Mr Trump's White House staff.
His subsequent attempt to take on the Republican establishment suffered a severe blow when Roy Moore, the Senate candidate he championed in a special election in Alabama, lost to a Democrat - the first time that party has won in the state in decades.
Mr Trump has recently taken to referring to Mr Bannon as "Sloppy Steve", a derogatory reference to his former aide's famously dishevelled appearance.
Mr Bannon had served as executive chairman of Breitbart since 2012, reports BSS.