Washington — President-elect Barack Obama, in a move long anticipated, has settled on his longtime friend Arne Duncan, the head of Chicago’s public-school system, as the new U.S. education secretary.

Mr. Obama plans to announce his nomination of Mr. Duncan tomorrow in Chicago, according to Democratic sources speaking on the condition of anonymity.

Mr. Duncan has been chief executive of the Chicago Public Schools for the past seven years, and has little policy-making experience in either postsecondary education or the federal government.

The nomination, which requires Senate confirmation, is one of the last to be made by Mr. Obama for his cabinet in preparation for his swearing-in as president, on January 20. —Paul Basken