Sebastian Fabijański was born 14 June 1987 in Warsaw. He studied acting in Wyższa Szkoła Komunikowania i Mediów Społecznych in Warsaw, then law in the University of Warsaw and again acting in National Academy of Theatre Arts in Kraków and in Aleksander Zelwerowicz National Academy of Dramatic Art in Warsaw. In 2015 Fabijański graduated from Aleksander Zelwerowicz National Academy of Dramatic Art in Warsaw with a MA degree in Acting.

In 2014 he won an award for the Professional Acting Debut at the 39th Polish Film Festival in Gdynia for his roles in films Jeziorak (English title Waterline) and 'Miasto 44 (English title Warsaw 44). In 2015 he won an Andrzej Konic Award for Acting Debut at the 29th Tarnów Film Awards for his roles in films 'Waterline (original title Jeziorak) and Warsaw 44 (original title Miasto 44).