Office of the Historian

Thomas Clifton Mann (1912–1999)

Career Foreign Service Officer
State of Residence: Texas
  1. Ambassador Extraordinary and Plenipotentiary (El Salvador)
    Appointed: October 11, 1955
    Presentation of Credentials: November 24, 1955
    Termination of Mission: Left post on September 24, 1957
    • Commissioned during a recess of the Senate; recommissioned on January 25, 1956, after confirmation.
  2. Assistant Secretary of State for Western Hemisphere Affairs
    Appointed: September 7, 1957
    Entry on Duty: August 28, 1960
    Termination of Appointment: April 20, 1961
    • Date of original commission as Assistant Secretary; prior to Aug 28, 1960, served as Assistant Secretary for Economic Affairs.
  3. Assistant Secretary of State for Economic, Energy, and Business Affairs
    Appointed: September 7, 1957
    Entry on Duty: September 30, 1957
    Termination of Appointment: August 28, 1960
    • Commissioned during a recess of the Senate; recommissioned after confirmation on Jan 27, 1958. Designated Assistant Secretary of State for Inter-American Affairs on this date. A personnel action assigned Mann to the position of Assistant Secretary for Inter-American Affairs effective Aug 7, 1960, but this date was probably an error for Aug 28, 1960. Mann’s commission expired Apr 20, 1961.
  4. Ambassador Extraordinary and Plenipotentiary (Mexico)
    Appointed: April 18, 1961
    Presentation of Credentials: May 8, 1961
    Termination of Mission: Left post on December 22, 1963
  5. Assistant Secretary of State for Western Hemisphere Affairs
    Appointed: December 21, 1963
    Entry on Duty: January 3, 1964
    Termination of Appointment: March 17, 1965
  6. Under Secretary for Economic Growth, Energy, and the Environment
    Appointed: March 11, 1965
    Entry on Duty: March 18, 1965
    Termination of Appointment: May 31, 1966