Sergio Freijo was born in Barcelona to a Galician father and an Asturian mother. He quickly developed an interest in theatre and began studying at Escola Eòlia. After graduating in Political Science, he auditioned for the Stella Adler Studio of Acting in New York, where he was accepted and spent two years.

In film and television, he has worked on Bird Box Barcelona, the second season of Warrior Nun — alongside Tristán Ulloa — and Afterburn, where he worked with Dave Bautista and Kristofer Hivju. His latest project has been Matar a un oso, in which he shares a storyline with Pol López and María Rodríguez Soto.

His first professional role in theatre was ten years ago, starring in Kyla by Lars Norén. He was also part of Malnascuts, a creative process at Sala Beckett where he worked alongside Laura Weissmahr, Elena Martín, and Àlex Monner. Most recently, he has worked under the direction of Romeo Castellucci in a production starring Isabelle Huppert.

Sergio is bilingual in Spanish and Catalan and speaks English fluently. He also has an advanced level of French; intermediate level in Italian, Galician, and Portuguese; and a basic level of Chinese. In addition, he masters different accents in both English and Spanish. He has also dubbed himself into Spanish and Catalan in projects he performed in on the big screen (Afterburn and Bird Box Barcelona).