Government and Department for Work and Pensions (DWP) CIO Joe Harley has said he will retire from both roles in the spring of 2012.
Harley has been DWP CIO for the last seven years, and became government CIO in January this year, replacing former CIO John Suffolk.
The process of finding his replacement will begin immediately, according to a statement, and the DWP and government CIO roles will be replaced seperately.
Harley has overseen the well-received government ICT strategy, released in March this year, and the Strategic Implementation Plan since taking on the role of government CIO.
He was responsible for a transformation programme at the DWP, which saw the department reduce headcount from 1,200 to 500. Harley has also overseen the establishment of the Universal Credit Programme.
The Universal Credit system is due for completion in 2013, and has been designed to unify the benefits system and make it real-time.
The DWP has an annual IT spend of £1.2bn.
Work and Pensions secretary Iain Duncan Smith said: "I would like to thank Joe for his significant and exceptional contribution to DWP and the government. He has been instrumental in building reform and modernising our approach to technology."
DWP permanent secretary Robert Devereux added: "Harley has been pivotal in establishing commercial arrangements which give value for money, and in the delivery of major changes to IT underpinning services which are critical for millions of people every day. The IT for Universal Credit, in particular, is on track. I wish him well in his retirement"
Minister for Cabinet Office Francis Maude said: "Harley's work [on the a new ICT strategy and strategic implementation plan] will ensure that the old siloed way of developing government ICT projects comes to an end, and leaves us with all departments working together to produce a fit-for-purpose and cost-effective ICT system potentially saving £1.4 billion over the next four years."
Deputy CIO Bill McCluggage announced he will be leaving his post earlier this month. He has said he will take up a new post with EMC Systems. The Cabinet Office has said the process of finding his replacement has begun.