 Active in progressive politics as a high school student, Castillo went into exile in El Salvador in 1954 after the overthrow of Guatemalan President Jacobo Arbenz by a Central Intelligence Agency-orchestrated coup d'etat.In El Salvador, Castillo met Salvadoran poet Roque Dalton and founded an influential literary circle.He spent the next several years in and out of exile, including a period of time spent in East Germany at the University of Leipzig.