Born to a planter, out of wedlock, Castillo Armas was educated at Guatemala's military academy. A protégé of Colonel Francisco Javier Arana, he joined Arana's forces during the 1944 uprising against President Federico Ponce Vaides. This began the Guatemalan Revolution and the introduction of representative democracy to the country. Castillo Armas joined the General Staff and became director of the military academy. Arana and Castillo Armas opposed the newly elected government of Juan José Arévalo; after Arana's failed 1949 coup, Castillo Armas went into exile in Honduras. Seeking support for another revolt, he came to the attention of the US Central Intelligence Agency (CIA). In 1950 he launched a failed assault on Guatemala City, before escaping back to Honduras. Influenced by Cold War fears of communism and the pressure from the United Fruit Company, in 1952 the US government of President Harry Truman authorized Operation PBFortune, a plot to overthrow Arévalo's leftist successor, President Jacobo Árbenz. Castillo Armas was to lead the coup, but the plan was abandoned before being revived in a new form by US President Dwight D. Eisenhower in 1953.