Ian Watmore, Permanent Secretary of the Cabinet Office, is leaving the civil service next month to focus on "non-executive" and "spousal" roles in charity, sports, academic and church activities.
Watmore, who was government CIO from 2004 to 2005, is responsible for the government's CIO function. Current government CIO Andy Nelson reports directly to him.
He also played an important role in establishing the Cabinet Office's Efficiency and Reform Group (ERG).
Francis Maude, Cabinet Office minister, said: "This group put in place tough cross-Whitehall controls on property, procurement and ICT in 2010. As a results we have helped departments deliver billions of pounds in cash savings for the taxpayer.
"He has assembled an enormously impressive team in ERG who will carry forward this crucial agenda."
Watmore will be returning to his home in the North West of England after seven years with the civil service.
Prior to his public role, Watmore held roles as chief executive of the Football Association, UK managing director at Accenture and a consultant at Andersen Consulting.