[1][2] Between July 2007 and April 2011, he served as the principal private secretary to chancellors Alistair Darling and George Osborne, and subsequently as a managing director for Bank of America Merrill Lynch.

The bank subsequently bid for lucrative roles advising UK Financial Investments on the sale of Northern Rock, which had been the subject of oversight by the Treasury while Rosenfield had been in office.

[2] This followed the fallout caused by the resignations of key Boris Johnson advisers Lee Cain and Dominic Cummings, and the appointment of Edward Lister as the acting chief of staff.

[12][13] Shortly after his appointment, in April 2021, Rosenfield was implicated in a potential lobbying scandal in relation to the proposed European Super League of major football clubs.

[18] In July 2021 it was reported by The Times that Rosenfield's leadership was unpopular among some Downing Street staff members, including Nikki da Costa, the director of communications.

[20] It was reported in The Sunday Telegraph in January 2022 that Rosenfield had attended a cricket game three days before the Fall of Kabul, for which the UK government was criticised in its response.

[22] Speculation arose that Rosenfield might be sacked by Johnson for his role in the controversy, amid further criticism that he had presided over a 'laddy' culture within Downing Street which had excluded female members of staff.