Although the family finances were damaged after the death of his father in 1910, Alföldi was able to begin his studies of classical history after his graduation from high school.
In later years he looked back on his service with pride and he retained an interest in military and strategic subjects throughout his life.
The Treaty of Trianon, which officially ended the war in Hungary and established its borders, was perceived as a humiliation to the country.
In the aftermath of World War I, national ties and boundaries that had been established over hundreds of years were dissolved and rebuilt.
Over the next 15 years Alföldi shaped the field of ancient history and archeology in Hungary, and was also recognized as an outstanding scholar by the international community.
Alföldi's work was not interrupted by the second world war, but the post-war influence of the Soviet Union over the Hungarian state put an end to his research.
The position afforded better pay and more opportunities for travel, and Alföldi would continue to work on projects at Princeton even after his retirement.
After emigrating, Alföldi expanded his areas of research into early Roman history and the eventual demise of the empire.
The murder of Caesar attested to the blindness and scrupulousness of the senatorial oligarchy, which in turn no way supported a republican order.
Here he highlighted not only the emotional and religious grounds for Octavian's approach after Caesar's death, but also the underlying tangible economic aspects.
In these two essays he describes both the religious foundations as well as the continuous development and official expressions of Roman rulers’ ideology.
Of particular importance was the cataloging of the so-called Contorniate coins, which opened up a new, hitherto almost unknown source, especially for the history of ideas of the late 4th and early 5th centuries.
What most interested Alföldi in the study of late antiquity, however, was the era between Constantine I and the victory of Christianity over paganism.
Also his annual organization of an international colloquium to the Historia Augusta, which was held on a regular basis for 20 years, contributed greatly to the study of late antiquity.
Just as Mommsen is regarded as the great organizer in the study of Roman inscriptions, Alföldi is thought of as the doyen of numismatics.
He wrote about the art of photographing of Greek vase paintings, the psychological foundations of witchcraft and the importance of the theriomorphic worldview among the peoples of North Asia.