[2] He attend Union Theological Seminary in Buenos Aires, Argentina, competing his studies in 1950,[3] and was ordained in the Evangelical Methodist Church of Uruguay.
In his first few yours of ministry, he pastored churches in the cities of Trinidad, Durazno, and Pasos de los Toros.
[1] From 1953 to 1954, he undertook a year of graduate studies with Karl Barth in Basel, Switzerland, with support from a grant by the World Council of Churches.
[1] During his pastorate there, he developed a religious television show which proved to be both popular and controversial because it addressed justice issues.
[5] In 1975, he authored Amidst Revolution, which reflected on the contemporary issues facing the Christian churches in Latin America.
[5] On October 14, 2009, Castro received the Orden de Bernardo O'Higgins, an award granted by the government of Chile to non-Chileans.