During his life he was a religious, a parish missionary, founder of two religious communities and a great promoter of devotion to the Sacred Heart and the Immaculate Heart of Mary. He joined the religious community of the Oratorians and was ordained a priest at the age of twenty-four. At that time, there were some severe outbreaks of terrible sickness, taking the lives of thousands of people, and he volunteered to care for the sick. He didn't want to risk bringing the disease to his fellow religious, so he lived in a huge barrel that had been turned on its side in the middle of a field during the plague.
After that time, he became a parish missionary. His gifts as preacher and confessor meant that people flocked to hear him. He preached over a hundred parish missions, some lasting from several weeks to several months.
He had a great concern for the spiritual lives of the clergy, and he realized that the greatest need was for seminaries. He had permission from his general superior and the bishop to do this work, but the a new superior decided he didn't like St. John Eudes or his work, so John decided it was best for him to leave the religious community. He immediately founded a new community, the Congregation of Jesus and Mary, which was devoted to the formation of the clergy by conducting diocesan seminaries, but there were some who tried to ruin this effort, too, until John finally had to give up that work.
In his parish mission work, John was disturbed by the sad condition of women and young girls living on the streets, but who wanted to escape their terrible existence. Temporary shelters were found but arrangements were not satisfactory, until St. John, with the help of others, took on this work by founding another religious community, called the Sisters of Charity of the Refuge.
He is probably best known for the central theme of his writings: Jesus as the source of holiness, Mary as the model of the Christian life. His devotion to the Sacred Heart and to the Immaculate Heart of Mary is what formed his own spiritual life.
Holiness is the wholehearted openness to the love of God. It is visibly expressed in many ways, but the variety of expression has one common quality: concern for the needs of others. We see how St. John Eudes carried out this concern in very practical ways.
O God, who didst wonderfully choose thy Priest Saint John Eudes to proclaim the unfathomable riches of Christ: grant us, by his example and teachings; that, growing in knowledge of thee, we may live faithfully by the light of the Gospel; through Jesus Christ thy Son our Lord, who liveth and reigneth with thee, in the unity of the Holy Spirit, ever one God, world without end. Amen.