“You are going to build the trade center,” Guy F. Tozzoli was told on his 40th birthday in 1962 by the head of the Port of New York Authority. Eleven years later, he had.

Mr. Tozzoli, among the most important figures in the development of the original World Trade Center in Lower Manhattan, died on Saturday in Myrtle Beach, S.C. He was 90.

His death was announced by the World Trade Centers Association, an international group that he helped found and then led for more than four decades.

As director of the World Trade Department of the Port Authority, Mr. Tozzoli not only superintended development of the twin towers, but was also given credit for having brought the architect Minoru Yamasaki to the job, after admiring a pavilion by Mr. Yamasaki at the 1962 World’s Fair in Seattle; for shepherding the enormously popular Windows on the World restaurant atop the north tower into existence with his friend, the restaurateur Joseph Baum; and for coming up with the idea — while shaving one morning — to use the tremendous volume of rubble from the trade center excavation as landfill for Battery Park City.