United States ambassador to Cuba from 1929 until his resignation in 1933.
Director and president of the Daniel and Florence Guggenheim Foundation which sponsored much of the research of Dr. Robert J. Goddard, upon which all modern developments of rockets and jet propulsion was based.
Served as president of the Daniel Guggenheim Fund for the Promotion of Aeronautics. This fund included an equipment loan for operating the first regularly scheduled commercial airline in the United States, provided for the establishment of the first weather reporting exclusively for passenger airplanes, and helped establish schools of aeronautical engineering.
Organized a Safe Aircraft Competition to encourage aerodynamic safety without loss of aircraft efficiency.