US President Donald Trump has replaced his acting chief of staff, Mick Mulvaney, whose departure had long been rumoured.
He said North Carolina lawmaker Mark Meadows would take over. The change had been expected for weeks.
Mr Trump said Mr Mulvaney would become US special envoy to Northern Ireland.
Mr Mulvaney was perceived to have implicated the president in last year’s impeachment inquiry in an off-the-cuff remark at the White House podium.
When Mr Mulvaney gave a rare White House press conference last October, he shrugged off criticism over an alleged corrupt deal with Ukraine by saying: “We do that all the time.”
Mr Trump was reportedly outraged by the gaffe.
Mr Mulvaney then walked back his comments in a written statement that said: “Let me be clear, there was absolutely no quid pro quo between Ukrainian military aid and any investigation into the 2016 election.”