Originally a student of Classics at a Jesuit University in Rio de Janeiro, Marcos Arruda decided to change his topic of study to Geology in the Federal University of Rio de Janeiro.

Soon after the military coup d’état of 1964, Marcos became involved in Ação Popular, a left-wing organization that gained momentum among the student movement in Brazil at the time.

Marcos moved to São Paulo in 1967. In 1968, he found a job as an unskilled worker in a foundry. Sadly, Marcos was suddenly arrested in São Paulo on May 11, 1970. He would be interrogated on fabricated charges and brutally tortured by military officers while imprisoned.

After being released from prison, he moved to the United States with his mother, Lina, where he founded the Committee Against Repression in Brazil and was involved in campaigns throughout the United States to denounce the Brazilian military regime.

Marcos has spent time at Brown University as a visiting professor. Marcos has remained politically active, and currently resides in Rio de Janeiro in an apartment close to his siblings and mother.