Richard Sharp has resigned after a report found he failed to declare two conflicts of interest during his appointment process.
Mr Sharp, a Tory donor, had helped arrange a meeting for Boris Johnson to meet with someone who could give him a personal loan.
He also told the prime minister in advance that he wanted the job – and the appointment panel was told he was the “only” candidate supported by ministers.
His old friend Sam Blyth, a Canadian businessman, went to Mr Sharp with an offer to help Mr Johnson as the then-prime minister struggled financially in 2020.
In a statement, he said: “Mr Heppinstall's view is that while I did breach the governance code for public appointments, he states that a breach does not necessarily invalidate an appointment.
“Indeed, I have always maintained the breach was inadvertent and not material, which the facts he lays out substantiate. The Secretary of State has consulted with the BBC Board who support that view.”