Castro was born in Hoboken, New Jersey. His parents were from Puerto Rico. In 1979, when he was 12 years old, he moved to Puerto Rico with his mother. After finishing military training, Castro went to university in Puerto Rico. While he was a student he went to many sports running competitions. After four years of university, Castro joined the US Army. He later trained to become an officer. He was blinded during combat in Iraq; while serving in 2006.