Alonso was born on October 17, 1500 in Oropesa, Toledo, Spain, to deeply Christian parents. When he was still young the family moved to the nearby city of Talavera de la Reina, where he received his schooling. At the age of 14 Alonso’s parents sent him to the University of Salamanca where his brother Francisco was already a student. At the time, Thomas of Villanova was preaching in Salamanca and many were touched by his words, including a number of young people who were drawn to religious life. Among them were the two Orozco brothers, Francisco and Alonso, who entered the novitiate together in 1522 at the monastery of San Agustin. On June 9, 1523 Alonso made his profession, but his brother was unable to do so because of illness and died shortly thereafter. Francisco's death had a deep effect on Alonso who began to suffer physical and spiritual afflictions that lasted for many years, all of which served to purify him, however, for he continued to live religious life with great fidelity. Following ordination he was assigned to preach and served, as well, as prior in various houses of his province. Later he volunteered to go as a missionary to Mexico but on the way he became ill and was ordered to return home. In 1554 he was named preacher of the royal court, but lived always as a simple friar, in absolute poverty and in the humblest of conditions. Ever attentive to the poor, the sick, and the imprisoned, he became known as ‘the saint of San Felipe’. Alonso was also a prolific writer, publishing about 50 books, including a commentary on the Rule, works on Saint Augustine and the saints of the Order, and his own Confessions. Moved by a desire for reform within the Order, he founded several friaries and convents of contemplative nuns. He died on September 19, 1591. His body is venerated in the church of the Augustinian nuns of Madrid. Alonso was beatified by Leo XIII on January 15, 1882 and canonized on May 19, 2002 by John Paul II.
Though called to exercise his ministry among the powerful and wealthy of his day, Alonso remained steadfastly faithful to the life of simplicity he had professed. His preference was to serve the poor and the needy, to whom he always remained available, and to use his talents in instructing the common people through his preaching and writings. He was one of the first to use the vernacular in his writings on prayer and contemplation precisely to benefit ordinary people.