Campbell Robb has been appointed director general of the Office of the Third Sector at the Cabinet Office.
Robb will join third sector minister Ed Miliband's staff in November from the NCVO, where he is currently director of public policy.
Robb's responsibilities will include looking into how the third sector can improve public services, helping to deliver government policies on social enterprise and co-ordinating cross-government delivery programmes.
For the past seven months, Robb has been working at the Treasury one day a week as lead adviser to the Government's ongoing third sector review.
His new appointment will cut short his secondment by five months.
Robb, who will be paid about £100,000 a year, leaves the NCVO after eight years of working on its campaigns.