She replaces Charles Roxburgh, who was appointed Second Permanent Secretary to the Treasury in June.
As the new Director General, Katharine Braddick will be responsible for all issues relating to financial services, the financial system and financial stability at the Treasury.
Ms Braddick is currently the Treasury’s Director for Financial Services (International and EU), having joined the department on secondment from the Bank of England in 2014.
Before joining the Treasury in 2014, Ms Braddick was Director of Prudential Policy at the PRA, Head of Prudential Banking Policy at the FSA, and Head of Department in the International Division (2008 -11).
She joined the FSA in 2003 from the Association of British Insurers, having started her career as a civil servant at the Department of Environment in 1996.