He served as the New York Port Authority's Chief Engineer in 1929 and is the designer of
many suspension bridges in New York City.
The first bridge that Ammann designed for New York City was the George Washington Bridge, completed in 1931, costing $59 million dollars. Another record breaking bridge he designed is The Narrows-Verrazano Bridge, which was the longest suspension bridge in the world at the time of its completion, in 1965.
These passages in to, and out of, New York City "bridged the gap" between conventional designs and modern technology. His structural engineering skills also led to the creation of the Throgs Neck Bridge, Bronx Whitestone Bridge, and the Bayonne Bridge. Ammann enjoyed an industrious career and a long life. He died the same year the Verrazano-Narrows Bridge was completed on September 22nd, 1965 in Rye, New York.