Robin Budenberg, chief executive of the organisation, which was set up to manage the governmentâs investments in banks, is to take over his duties.
Tim Sykes will become head of the markets investments strategy where his responsibilities will include monitoring the bodyâs strategy and performance.
Mr Budenberg of UKFI said: âWe are obviously sad that John has decided to leave but fully understand his decision to develop his career elsewhere as UKFI moves into a new phase of its development.
âIn my short time here, I have been deeply impressed by the respect in which John is held by our stakeholders. The board is grateful for his enormous contribution in successfully resolving so many challenges during 2009.â
Mr Crompton described the role as âvery intense and enjoyableâ and thanked the UKFI for the opportunity to work with the government in its response to the financial crisis.
The UKFI was established in November 2008 to monitor the authorityâs investments in struggling banks including RBS, Northern Rock and Bradford and Bingley.
By Jim Ottewill