Hoveyda joined the foreign ministry in the early 1940s. A participant in the final drafting of the Universal Declaration of Human Rights, he worked in UNESCO from 1951 to 1966. In the late 1960s, he returned to Iran and worked in the Iranian Foreign Ministry as the undersecretary for international and economic affairs. He was also deputy foreign minister. From 1971 to 1979 he represented Iran at the United Nations.