While the vast majority of cases have been in China, the virus has spread to some two dozen countries abroad, including five British nationals infected in a French ski resort.
The American man died on Thursday in Wuhan, epicentre of the virus outbreak in the central Chinese province of Hubei, a U.S. embassy spokesman said in Beijing on Saturday.
"We offer our sincerest condolences to the family on their loss," he told Reuters. "Out of the respect for the family's privacy, we have no further comment."
A Japanese man in his sixties and hospitalised with pneumonia in Wuhan, capital of Hubei, also died after suffering symptoms consistent with the new coronavirus, Japan's foreign ministry said.