Donald Trump has named congressman Mark Meadows as his new chief of staff, replacing Mick Mulvaney, who had been acting in the role for more than a year.

Trump announced the staff reshuffle in Friday night tweets, saying Mulvaney would become the US special envoy for Northern Ireland.

“I have long known and worked with Mark, and the relationship is a very good one,” Trump said.

The long-rumored move makes Meadows, who announced he was not seeking re-election for his House seat from North Carolina, in effect Trump’s fourth chief of staff since taking office in 2017.

The decision comes as the Trump administration has faced criticism for its handling of the coronavirus outbreak. Mulvaney had been leading the interagency response to the virus until Trump designated the vice-president, Mike Pence, to lead the whole-of-government effort more than a week ago.

Meadows, a conservative four-term congressman from North Carolina who previously chaired the Freedom Caucus, has long been a close ally to the president. He’s also been a staunch proponent of Trump’s border wall in Congress.

He replaces Mick Mulvaney, who became a key figure during the impeachment proceedings. Fiona Hill, a national security council member, testified that Gordon Sondland, the ambassador to the European Union, said that Mulvaney had approved a White House meeting with Trump for the Ukrainian president on condition Ukraine announced investigations tied Joe Biden. Hill’s account was corroborated in testimony by another firsthand witness to the conversation, Lt Col Alexander Vindman.

Mulvaney himself said in a televised October press conference that the White House had conditioned military aid on investigations in Ukraine, but he later denied he had said that.