NEW YORK (AP) – Dick Heyward, who served as UNICEF’s senior deputy executive director for more than three decades, has died, the agency said Thursday.

Heyward, who retired in 1981, died Wednesday at North Shore University Hospital in Manhasset following a long illness. He was 90.

UNICEF Executive Director Ann M. Veneman called Heyward “truly one of the giants” in UNICEF history.

“He was a man of extraordinary dedication and drive and he had a profound influence on UNICEF,” she said in a statement. “His legacy lives on in UNICEF today.”

Heyward served as the organization’s senior deputy executive director from 1949 until his retirement and was regarded as the “intellectual powerhouse behind much of UNICEF’s policy” during that time, Veneman said.

In 1981, then-UNICEF Executive Director James Grant called Heyward “a living monument to everything for which UNICEF stands. … Every good and brave endeavor for which UNICEF has earned worldwide applause has been touched by his mind and by his hand.”

E.J. Richard Heyward was born on his family’s apple farm in Tasmania, Australia, on Sept. 22, 1914. He was educated in Tasmania and at the London School of Economics and served as the first secretary to the Australian Mission to the United Nations from 1947 to 1949. He was appointed UNICEF’s deputy executive director in 1949.

In 1975, Heyward was appointed senior deputy executive director of UNICEF with the rank of assistant secretary general of the United Nations.

After his retirement he continued to work for UNICEF, the World Health Organization and the World Bank. He traveled to places like Tanzania, Sudan, Niger, Mali, Somalia, Rwanda, Zaire and Mozambique until he suffered a stroke in 1997, at the age of 82.

He is survived by his wife, Elisabeth, a retired interpreter at the United Nations; his sons Andrew, who is president of CBS News, and Peter, a Washington, D.C. lawyer; and seven grandchildren.

Funeral arrangements were private.