In 1914 he was elected provincial councilor for the Spezzano Grande district, with a program that included, among other things, the abolition of private property, religion and institutions of the time.

To respond to the Matteotti crime committed by the fascists, the communists proposed a general strike and remained in Parliament unlike the other groups that went to the Aventine.

In the spring of 1925, he signed the initiatives of the Committee of Understanding, promoted, among others, by the deputies Onorato Damen, Bruno Fortichiari and Luigi Repossi.

[3] Fausto Gullo was the first to propose the establishment of the Constituent Assembly during the first meeting of the first Council of Ministers of liberated Italy, as reported in his diary of those days.

As a deputy of the Constituent Assembly he contributed to the elaboration and affirmation of some values of the Fundamental Charter, in particular by discussing the following topics in the Assembly: He held the position of Minister of Agriculture until 1946, in the Second Government of Alcide De Gasperi, when he was replaced in Agriculture by the Christian Democrat landowner Antonio Segni and was appointed Minister of Grace and Justice in place of Palmiro Togliatti.