Larrea Holguín was born in Buenos Aires, Argentina, while his father performed a diplomatic service for Ecuador before the Argentine government.

As a student in Italy, Larrea Holguín met Josemaría Escrivá de Balaguer, founder of Opus Dei, and after this meeting, in 1949, he requested admission into this institution of the Catholic Church.

In 1983, Pope John Paul II appointed him the first military bishop of Ecuador and in 1988 he moved him to Guayaquil, where he served as Archbishop from 1989.

Since his retirement, he dedicated himself to the service of Opus Dei, and to the creation of numerous religious and legal works.

He also educated people in the Institute of High National Studies, the Academy of Diplomacy and seminaries of Ibarra and Guayaquil.