Stefanos furthered his studies in France following the same path of Timoleon Argyropoulos, Dimitrios Stroumpos, and Vassilios Lakon.

In France, Stefanos studied with Jean Gaston Darboux, Camille Jordan, and Charles Hermite.

He wrote articles in the fields of mathematical analysis, higher algebra, theoretical mechanics, and topology.

[6] He was also a professor at the National Technical University of Athens and the Hellenic Naval Academy.

Stefanos was an invited speaker at the International Congress of Mathematicians in 1897 at Zurich, in 1900 at Paris, in 1904 at Heidelberg, in 1908 at Rome, and in 1912 at Cambridge (England).

[7] Stefanos was born on the island of Kea, where his father worked as a school teacher.

In 1883, Stefanos proved that the theorem fails when three-dimensional hypercomplex numbers are applied.