He was an adjunct professor at St. John's University and president of the Africa Service Institute in New York City, from 1959 to 1967.

[2] A former consultant for the National Urban League in New York and chairman of Seton Hall University, he was appointed by President Richard Nixon as ambassador to Burundi in 1969, senior advisor to the US delegation to the UN General Assembly in 1970, and ambassador to Uganda from 1972 to 1973.

[3] In 1989 he was appointed by President George H. W. Bush as Ambassador Extraordinary and Plenipotentiary of the United States of America to the Holy See.

According to the Associated Press, his first instruction, since declassified, was to influence the Vatican to recognize the state of Israel, something which was done a few years later in 1993.

Melady was an authority on Afro-Asian and Central European Affairs and the author of 16 books and more than 180 articles, including Western Policy and the Third World, Uganda: The Asian Exiles, The United States and the Vatican in World Affairs, and "Bosnia and Herzegovina: The Future?