He was born March 9, 1568, and was the oldest of seven children to be born to Ferrante Gonzaga, Marquis of Castiglione, and Marta Tana di Santena, the daughter of a baron.
As the oldest son, he was expected to inherit his father's title and so received vigorous military training from a young age. Growing up in a violent Renaissance Italy, he witnessed the murders of two of his brothers. At 8, he was sent to Florence for further education and there fell ill with kidney problems that plagued him his whole life. While ill, he devoted much of his time to learning about the saints and praying, and is said to have taken a private vow of chastity at the age of 9.
After returning to Castiglione, he met Cardinal Charles Borromeo and received his First Communion from him on July 22, 1580. He felt strongly called to be a missionary, and practiced teaching catechism classes to young boys in Castiglione.
His family moved to Spain in 1581 to assist the Holy Roman Empress Marie of Austria. It was here that Aloysius decided to join the Jesuits, but was unable to due to his father.
The family returned to Italy in 1584, and many relatives attempted to convince Aloysius, if not to abandon his desire to be a priest, then instead to become a secular priest, and so maintain his inheritance to no avail. In November 1585, Aloysius gave up his inheritance and joined the Jesuits.
He continued to have health problems, not only with his kidneys, but also with skin disease, chronic headaches, and insomnia.
In May 1590, he claimed that the Archangel Gabriel had appeared and told him that he would die within a year. In 1591, the plague broke out in Rome, and the Jesuits opened a hospital to care for them. Aloysius volunteered and was placed in a ward without plague victims because they did not want to lose him. None the less, one of the men in the ward had the plague, and within a short time Aloysius began to show signs of it himself. However, to everyones surprise, he recovered, though his health was worse than ever.
While he was ill, he spoke often with his confessor, the cardinal and later saint, Robert Bellarmine, and told him that he had received another vision, that said he would die on the Octave of the feast of Corpus Christi. On that day, he appeared to be quite well in the morning, but gradually got worse through out the day. Bellarmine gave him the last rites, and he recited the prayers for the dying. Aloysius died just before midnight.
He was beatified by Pope Paul V on October 19, 1605 and was canonized by Pope Benedict XIII on December 31, 1726.
