oris Johnson has appointed former Treasury official Dan Rosenfield as his new chief of staff.
Mr Rosenfield, who is currently the head of corporate clients and Uk business at strategic advisory firm Hakluyt, will begin work at Downing Street on December 7.
His appointment comes two weeks after a power struggle erupted in Number 10 over plans to make former aide Lee Cain the new chief of staff.
Lord Udny-Lister is set continue to serve as acting chief of staff until January 1, 2021, when Mr Rosenfield will formally take over, Downing Street said.
He was previously a managing director in investment banking at Bank Of America, and worked for more than a decade in the Treasury, including four years as principal private secretary to Chancellors Alistair Darling and George Osborne.
Mr Rosenfield is also the chairman of World Jewish Relief, the British Jewish community’s humanitarian agency.