[2] In 1928 he won a silver medal in the art competitions of the Olympic Games for his verse-drama "Icaro", an anti-fascist allegory disguised as a retelling of the Greek myth.

[2] In the summer of 1930, De Bosis resigned from the Italy-America Society to found the "Alleanza Nazionale" and concentrate on the group's mission—the clandestine circulation of anti-Fascist newsletters in Italy.

Inspired by another anti-Fascist (Giovanni Bassanesi) who earlier had flown over Milan dropping leaflets denouncing Il Duce, de Bosis decided to embark upon a similar flight over Rome.

On 3 October 1931, with only seven-and-a-half hours flying time and a partially filled fuel tank, De Bosis took off from Marseille on a small Klemm L 25, heading for Corsica and then Italy.

In 1938, actress Ruth Draper made an endowment to maintain a lecture series on Italian culture, history and society, named after De Bosis in Harvard University.