The United States (U.S.) immediately recognized the new nation and moved to establish diplomatic relations.

The U.S. embassy in Dar es Salaam opened on the day of Tanganyika's independence.

William R. Duggan served as the chargé d'affaires ad interim pending the appointment of an ambassador.

The U.S. established an embassy in Zanzibar on December 10, 1963, with Frederick P. Picard III serving as chargé d'affaires ad interim.

In lieu of an ambassador, Frank C. Carlucci III was serving as the chargé d'affaires ad interim and continued in that capacity until the U.S. embassy was downgraded to a consulate general on June 27, 1964.