Pate served as the first executive director of the United Nations Children's Fund (UNICEF) from 1947 until his death in 1965, after being proposed by the Chairman Ludwik Rajchman.

At Princeton he was a member of Phi Beta Kappa, worked on the undergraduate Red Cross Committee, and earned a bachelor of science degree in mathematics and physics in 1915, with high honors.

[5] He went to work for the First National Bank in Hartley, Iowa, where his uncle was president, immediately after graduation and stayed until the United States joined World War I.

After a great deal of persuasion, he worked for Herbert Hoover's Commission for Relief in Belgium, which began a lifelong friendship and collaboration.

Initially, UNICEF was charged with combating the threats posed to children in Europe from disease and famine after World War II.

The growing concern about child welfare and survival rates in developing countries, either from disease or starvation, led to the establishment of UNICEF as a continuing agency in 1953.

[3] Pate died suddenly of a heart attack at Bellevue Hospital in Manhattan on January 19, 1965, only a few months before he was to retire.