Castaño was born July 2, 1957, in Amalfi, a small village in the Antioquia Department in central Colombia. He was the sixth among twelve siblings of a family of farmers. When he was 12 years old he  dropped out from school to help his father on farming duties.
Castaño was born on July 2, 1957, in Amalfi, a small village within the Antioquia Department of central Colombia. He was the sixth among twelve siblings from a farming family. At age twelve, he left school to assist his father with agricultural tasks.