He wrote prolifically, and some of his work (following the intuition-led approach of Federigo Enriques) has subsequently been shown to be not rigorous according to the then new standards set in particular by Oscar Zariski and André Weil.

Although he had to earn a living while conducting private lessons, Francesco Severi managed to continue his studies and enroll in the engineering course at the University of Turin.

Due to the influence of courses by Corrado Segre, Severi quickly found a passion for pure mathematics.

After his thesis, he became assistant to Enrico D'Ovidio at the University of Turin and from 1902 to 1905, he was a lecturer in projective and descriptive geometry.

Nevertheless, Severi would remain without reaction against fascism and would accept the application of the racial laws.

In 1959, he converted to Catholicism and published his autobiography Dalla scienza alla fede (1959), he repents of his lack of political discernmentMathematics is the art of giving the same name to various things, and mathematicians often make mistakes in politics, because it is, conversely, the art of giving different names to identical things.

All the mathematical works of Francesco Severi, except all books, are collected in the six volumes of his "Opere Matematiche".