Bradford & Bingley chief executive Christopher Rodrigues has been appointed to the board of the Financial Services Authority.
Treasury chief secretary Alistair Darling announced the appointment of Rodrigues and three others last week.
The other directors are Scottish Consumer Council chairman Deirdre Hutton, Morgan Grenfell Asset Management chief executive Robert Smith and Stephen Thieke, managing director of JP Morgan's corporate risk management division.
All four have been appointed for a three-year term under the existing Financial Services Act 1986.
Brian Williamson has been reappointed for a further year from November 3.
The Treasury says the appointments, made by Chancellor Gordon Brown and Bank of England governor Eddie George, reflect the Government's wish to see a broadly-based board.
Darling says: "The authority has a major task ahead of it to implement our reform of financial services regulations. I am grateful to the board for taking on that responsibility."