In 2001, De Gregorio began his acting career at the age of six in the television series Chiquititas.
[4] In 2003, he makes a small participation in the television series Tres padres solteros.
From 2007 to 2010, he was part of the cast of the youth television series Casi Ángeles, Stéfano de Gregorio played the co-starring role of León "Lleca" Benítez.
In 2011, he was the Host of Súper Bonus, a micro program where they spend the behind the scenes of the series Supertorpe.
In 2019, he was part of the play 100 metros cuadrados, with Florencia Bertotti and María Valenzuela directed by Manuel González Gil.