Carby is the second Metro Bank director to have left in the two months since a £900m accounting error halved the bank’s share price.
In January, the bank revealed it had miscalculated the low-risk weightings on part of its loan book. This meant it would have to increase the total of its risk-weighted assets by £900m to £8.9bn.
Metro Bank belatedly admitted that the Bank of England’s Prudential Regulation Authority had found the error, having said previously that an internal review had brought it up.
Carby had been with the bank for nine years, since its founding in 2010. His departure will be effective April 30.
In a statement, Metro Bank thanked Carby, whose work as a founding non-executive director had “a significant contribution to the success of the bank during his tenure”.