Special advisers advise ministers - they have no responsibility of their own. But they are different from other civil servants because they focus on the interests of the political party of ministers.
Professor David Egan replaces Dr Rachel Jones who now heads up the Sector Skills Council.
His remit is education and lifelong learning but he could work outside this area. Duties include reviewing papers that go to ministers, contributing to policy development, liaising with the Labour party and other groups working in the education policy area, preparing speeches, and helping with media issues.
Education's best-known special adviser was Conor Ryan, who worked for David Blunkett when he was education secretary in Westminster.
Peter Black, chair of the Assembly's education committee, said: "I think special advisers are useful for providing a different perspective - but we don't want too many."