Church leaders Pope John Paul II and Cardinal Carlo Caffarra have praised Portillo as a faithful servant of God.

In 1935, he joined Opus Dei and was subsequently ordained to the priesthood on June 25, 1944 by Bishop Leopoldo Eijo y Garay of Madrid as one of the first three men ordained for Opus Dei [1] He continued his studies to obtain a doctorate in Philosophy and Letters in history in 1944 from Central University of Madrid, with a dissertation entitled Discoveries and Exploration on the California Coast.

[2] In 1948 he earned a Doctorate in Canon Law from the Pontifical University of St. Thomas Aquinas, Angelicum[3] He then dedicated himself exclusively to the ministry and government of Opus Dei as its Secretary General.

In 1991, he was consecrated a bishop by Pope John Paul II, with Archbishops Giovanni Battista Re and Justin Francis Rigali serving as co-consecrators.

[1] Later that day, Pope John Paul II came to pray before del Portillo's remains, which now lie in the crypt of the Church of the Prelature, Our Lady of Peace at Bruno Buozzi 75, Rome.

It discussed the presence of the priest in the world, and why he needed a good formation in the basic human virtues in order to serve the men and women of his time.

"Not a week had gone by after the close of the Council when Cardinal Ciriaci, president of the commission of which Don Alvaro had been secretary, sent him a note expressing heartfelt gratitude and congratulations for the happy conclusion of a great achievement."

Ciriaci said: (History would regard this decree as) "a fresh, and practically unanimous, confirmation by the Second Vatican Council of ecclesiastical celibacy and the exalted mission of the priesthood."

On his death, John Paul II recalled del Portillo's "zealous priestly and episcopal life, the example he always gave of fortitude and of trust in divine providence and his fidelity to the See of Peter.

[citation needed] In 2004, the Cardinal Vicar of Rome, Camillo Ruini, said "The rather frequent occasions that I had to meet Bishop del Portillo imprinted on my soul the conviction that I found myself in the presence of an exemplary pastor."

He added: "In the firmness of his adherence to the doctrine of the Church, in his union with the Pope, in his pastoral charity, in his humility, and in his balance, he exhibited an extraordinary interior richness."

"[citation needed] Ruini said that there is a desire for a "quick beginning of this cause of canonization" on the part of "so many members of the ecclesiastical hierarchy and of the people of God."

On July 5, 2013 Pope Francis published a decree from the Congregation for the Causes of the Saints declaring the miraculous character of a cure of a Chilean boy attributed to the intercession of the del Portillo.