His family name is a corruption of Speyer, a town in the Rhineland which once had a significant Jewish community, but he reminisced that in the U.S. it often led people to mistake him for a Greek American.

His family emigrated from Germany just a month later, in December 1938; they passed through New York where their relatives had earlier fled, before settling in San Antonio, Texas.

[5] In a news interview a few years after his arrival, he expressed his disappointment at the relative absence of "wild west heroes" and American Indians in Texas, contrary to the image of the state that he had formed from the Western fiction popular in his native Germany.

[2] He stated that he had originally wanted to attend the University of Texas at Austin, but his mother encouraged him to apply to Harvard instead after hearing that a distant cousin had also been accepted.

[8] In July 1975, President Gerald Ford nominated Spiro to succeed C. Robert Moore as United States Ambassador to Cameroon, with concurrent accreditation to Equatorial Guinea.

Spiro and Consul William C. Mithoefer Jr. had nearly finished one of their regular visits to Equatorial Guinea when Equatoguinean Deputy Protocol Director Santiago Nchama presented them with a letter accusing the U.S. government of engaging in subversive activities in the country and complaining about U.S. foreign and domestic policy, including the Vietnam War and U.S. nuclear weapons.

A few days later, Equatorial Guinea's foreign ministry sent a telegram to the State Department announcing that the two U.S. diplomats were barred from returning to the country.

[2] His son Alexander married Vanessa Daryl Green of Potomac, Maryland at the Metropolitan Club of the City of Washington in May 1993; DC Circuit judge Laurence Silberman performed the ceremony.