William Howard Taft III was born on August 7, 1915, and was the eldest of four sons born to Robert A. Taft (1889–1953) and Martha Wheaton Bowers (1889–1958),[3] daughter of Lloyd Wheaton Bowers (1859–1910), the former solicitor general of the United States from 1909 to 1910.

[9] After graduating from Princeton, Taft taught English at the University of Maryland and Haverford College.

[9] In 1949, he went to Dublin as part of the Marshall Plan aid mission and worked for the Central Intelligence Agency and the Defense Department from 1951 to 1953.

His task as ambassador was made easier by the fact that John A. Costello (Taoiseach, 1954–57) was a personal friend; Taft described Costello as "pleasant and unassuming" whereas he had found Éamon de Valera "formal and aloof".

In 1957, Eisenhower appointed R. W. Scott McLeod as his successor to the Ambassadorship and Taft returned to the State Department as a member of its policy planning staff.