Aldermore chief financial officer James Mack will take responsibility for the its mortgage division on an interim basis until a permanent appointment is made.
The bank confirmed to Mortgage Solutions that the change would take effect from 5 April.
Mack will replace outgoing group managing director of mortgages Charles Haresnape who announced his departure in February.
He is joining Shariah compliant investment bank Gatehouse Bank.
Mack will remain on the Board and also continue in his role as chief financial officer.
Owain Thomas is features and contributing editor of Mortgage Solutions and editor of Specialist Lending Solutions.
He also has experience in the protection, pensions, workplace benefits and HR areas.
Owain has won two Headline Money Awards and the Protection Review's Journalist of the Year award.