Rojas was born in La Plata, and began his professional acting career in 1998, when he was 12 years old: he was cast as Yago in Cris Morena's production, Chiquititas.

[1] In 2002, he renewed his contract with the Cris Morena Group and was cast for the role of Pablo Bustamante in the Martín Fierro Award—nominated hit television series Rebelde Way.

Along with former Chiquititas fellows Camila Bordonaba, Felipe Colombo and Luisana Lopilato, he formed a music band, named Erreway, which sold more than 10 million compact disc units worldwide.

In 2004, Rojas starred in the El Trece series Floricienta, his third consecutive project with the Cris Morena Group in the span of seven years.

[4] In 2006, he once again worked with Cris Morena on television series Alma Pirata, opposite Luisana Lopilato, Mariano Martínez and Elsa Pinilla.

In 2008, Rojas signed a contract with the Cris Morena Group and the Disney Channel Latin America for a new television sitcom, Jake & Blake, his first project in English.

[11][12] During the development of Rebelde Way, Rojas and his co-stars: Luisana Lopilato, Felipe Colombo and Camila Bordonaba have become the members of the band Erreway.

In 2010, Bordonaba and Colombo began their independent musical project, La Miss Tijuana, marking the final split of Erreway.