In June 1950 he entered the Central Seminary, University of Santo Tomas, Manila, to take up philosophy and theology.

Dean was ordained a priest on 30 November 1956 by Cardinal Julio R. Rosales, Archbishop of Cebu, at a Mass Ordination in Manila during the II National Eucharistic Congress.

Appointed Vicar Forane of the Vicarial District of Santo Niño in Cebu, promoted as Honorary Prelate, elevated to Protonotary Apostolic Supernumerary, and appointed as parish priest of San Nicolas, Cebu City.

He received the pallium from the hands of Pope John Paul II on the Solemn Ceremony on the Feast of Sts.

During his incumbency, he founded the St. John the Evangelist School of Theology in 1988 and constructed the Archdiocesan Chancery during the 1990s.