Jeffrey will lead the new directorate that was created when responsibilities for children and families were transferred to the Department for Education and Skills in June.
He will be responsible for advising Charles Clarke, the secretary of state for education and Margaret Hodge, the minister for children young people and families.
He will also be a key figure in achieving the government's goal of fully integrated children's services and the proposals put forward in the green paper on children.
Jeffrey will take up the post on 10 November.
His background includes previous jobs in the DfES on low achievement, behaviour and attendance at school, special educational needs, and extended schools.
Between 1998 and 2000 he was director of children's services in the Department of Health, leading the Quality Protects Programme and and the NHS Plan Children's Taskforce. He has also worked on projects including Sure Start, and the social exclusion unit's reports on teenage pregnancy and education of children in care.
